Heavy Duty Remanufactured Electrical...

Heavy Duty RemanufacturedElectrical Components

Alternators - Starters - Switches

P-EL0698$10.00

Section 1: General

Warranty Policy 1-2Tag Identification 1-3Abbreviations 1-3Common Returns 1-4

Section 2: Heavy Duty Alternators

Replacement Determination 2-3Installation Instructions 2-4Cooling Fans and Pulleys 2-5Fan & Pulley Identification 2-6Delco Alternators 2-9Leece Neville Alternators 2-17Motorcraft Alternators 2-18Motorola Alternators 2-18Thermo King Alternators 2-19

Section 3: Heavy Duty Solenoids

Rotational Instructions 3-2Delco Solenoids 3-2Leece Neville Solenoids 3-5Series Parallel Switches 3-5

Section 4: Heavy Duty Starters

Replacement Determination 4-3Installation Instructions 4-4Identification Aids 4-5Delco Remy Starters 4-7Leece Neville Starters 4-14Prestolite Starters 4-15Ford/Mitsubishi Starters 4-16Thermo King Starters 4-16

Section 5: Wiring System Checks & Diagnostics

Quick Reference 5-3Troubleshooting Guide 5-4Diagnostic Procedure 5-6Series/Parallel Troubleshooting 5-24

Table of Contents

Notice: The information and data contained in this catalog is based on the latest information available at the time of publication.Although every attempt has been made to ensure the accuracy of the information contained in this catalog, we will not be heldresponsible for errors or omissions or problems arising from the use or misuse of the information it contains.

Copyright 1998, Precision Rebuilders, Inc.

Section1

GeneralInformation

NATION WIDE WARRANTY

Precision Rebuilders is an established member of National Rebuilders Warranty Service/APRA Service Assurance Plan. This service provides our customers with the confidenceof a Nation – Wide Warranty program throughout the United States and Canada.

The purchaser needs only to fill out and return the registration card and keep the warrantycard with the vehicle. Should a problem occuraway from your area, simply call the toll freenumber on the warranty card, give them the card number for verification, and the caller willbe referred to the nearest participating member. If it is determined that the problem is dueto a defect in our product, the unit will be repaired or replaced at no cost to you.

The Nation – Wide coverage is good for the entire length of the 1 year product war-ranty at no additional cost to you.

Limited Warranty

Precision Rebuilders guarantees all remanufactured products to be free of defects inworkmanship and material for a period of one year from the date of installation when suchparts are used in strict accordance with the proper application, installation, and mainte-nance as prescribed by the original manufacturer.

All warranty claims must be accompanied with an exp;anation of why the unit was removedfrom the vehicle. All units claimed defective should be returned, freight prepaid, within 30days. After inspection of the unit, a final decision will be made as to whether the unit iscovered under the terms of this warranty. You may request a report of our findings. Wereserve the right to repair, replace, or credit warrantable units at our descretion.

This warranty is in lieu of, and excludes all other warranties, expressed or implied, arisingby operation of law or otherwise, including any warranty or merchantability or fitness for aparticular purpose, and in no way will the manufacturer be liable for incidental or conse-quential damage.

1-2

Line 1: our Line Code and Part Number DRS STT7296

Line 2: Unit Type and Core Class 42MT Starter (162)

Line 3: Serial Number 0598

Copyright 1998, Precision Rebuilders, Inc. 1-3

Abbreviations

C.E. Commutator EndC.W. Clock-wiseC.C.W. Counter Clock-wiseD.E. Drive EndD.E.H. Drive End HousingGrd. Pl. Ground PolarityL.H. Lever HousingO.C.P. Over Crank ProtectionS.R.E. Slip Ring EndDr. Th. Drive TeethAmp. Amperage

Tag Identification

Line 1: our Line Code and Part Number DRA DR4058

Line 2: Unit Type and Core Class 21SI Alternator (118)

Line 3: Serial Number 0598

Part # DRS STT7296Type: 42MT STARTER (162)Serial# 0598

Remanufactured in St. Clair, Mo USA

Part # DRA DR4058Type: 21 SI ALT (118)Serial# 0598

Remanufactured in St. Clair, Mo USA

COMMON RETURNS

1-4 Copyright 1998, Precision Rebuilders, Inc.

Installation of alternator withoutdisconnecting battery cable

Overtightening of alternator

Unit dripping with oil and antifreeze Improper installation of pulley

Overtightening of electrical connections Hot spot on switch

Section2

Heavy DutyAlternators

Replacement Determination

If the wiring in the circuit is adequate, adjust the belts(s) (if any), tighten the mounting boltsand ground wire. Then test the alternator output as follows:

1. Vehicle is at shop temperature.

2. Connect the carbon pile and voltmeter across the batteries of the vehicle.NOTE: On 24-volt vehicles, connect the carbon pile across one 12-volt battery.Connect the voltmeter across the normal 24-volt battery connection. An inductiontype ammeter (clamp around) has its pickup clamped around the alternator outputwire.

3. With no electrical loads turned on, start up the engine. Fast idle until the voltagestabilizes (does not increase) for two minutes. Voltage then should not exceed 15volts (30 volts for a 24-volt system).

4. Speed up the engine and turn on carbon pile until the ammeter shows output hasreached the highest value. Record it.

5. Turn off carbon pile and engine.

Rated output is stamped on alternator case or nametag. If current output measured is notwithin 10% of rated output, or the voltage exceeds the maximum limits, replace the alternator.

Typical 12 volt system shown

HEAVY DUTY ALTERNATORS

2-3

INSTALLATION INSTRUCTIONS

1. The original alternator may have failed due to external causes. If the trouble is notcorrected, the newly installed alternator will fail also.

2. Turn ignition switch and all lights and accessories off.3. Disconnect negative battery cable.4. Recharge battery if needed. It must be fully charged and in good condition. A

hydrometer reading between 1.225 and 1.26 on each cell means battery is okay.5. Identify, tag or mark each wire to insure reconnection to the proper terminal.6. Remove wires and connections from the alternator.7. Remove the old alternator, loosening the belt-tensioning bolt first.8. Place remanufactured alternator on mounting bracket, insert and tighten mounting

bolts finger tight.9. Place belt on alternator pulley, make certain belts are properly aligned. Check to see

that belt is not cracked, glazed or oil soaked.10. Reconnect wires to their proper terminals.11. Adjust belt to correct tension; tighten belt tensioning and mounting bolts. Reconnect

negative battery cable. Be certain connections are clean and tight. An alternatorcannot withstand reversing polarity of the battery cables, booster cables or lead wires.Even momentary contact may destroy the alternator diodes.

COOLING FAN & PULLEY

When servicing or replacing alternator, always inspect fan and pulley for wear. Missing orbroken fans should be replaced to insure proper cooling. Worn “V” grooves in pulleys willcause belt slippage, creating excessive heat causing bearing failure, or excessive belt ten-sion also leading to bearing failure. The information on the following pages is a guide to themost popular replacements. Others are available upon request.


2-4

25-105Application: Delco 25SI, 27SI-Type 200,

29SI, 30SI & 40SI Series Alt.Replaces: 1969481

25-109Application: Delco 20 & 21SI Series Alt.Note: Bi-directional model, for CW modeluse part number 1624P.Replaces: 10467272

1624PApplication: Delco 21SI Series AlternatorsNote: Clockwise model, for bi-directionalmodel use part number 25-109.Replaces: 10471121

25-500Application: Leece Neville 2300-2800JBand 4425-4750J Series

107-97Application: Leece Neville (Motorola)Load Handler Alternators, MA9124& MA9156Replaces: 107-97

HEAVY DUTY ALTERNATORS - FANS & PULLEYS

2-5

25-201Application: Ford Truck AlternatorsReplaces: D0AZ 103A3101, GP-496

Dimension“A”

Face of Fan to Center of First Belt

Dimensions indicate:W (Groove Width) x OD (Outside Dia.) x B (Bore)

NOTE: 1/2" wide belts are approximately 5/8" betweencenterline of grooves on multi-grooved pulleys.

“A” Dim. Pulley Chart

Pulley P/N “A” Dim.24-1500 0.56"24-1501 1.30"24-1502 1.30"24-1503 0.66”24-1504 0.94"24-1505 0.51"24-1506 0.56"24-1507 0.69”24-1508 0.96”24-1509 0.57”24-1750 0.37”24-1751 0.35”24-1752 0.30”24-1753 0.46”24-1754 0.35”24-1755 0.36”24-2500 0.56"24-2501 0.56"24-5500 0.58"24-5501 0.61”

24-1500 Double GrooveApplication: Delco 25SI, 27SI-Type 200, 30SISeries & Leece Neville 2300-2800JB Series Alt.Dim: 1/2"W x 3 1/8"OD x 7/8"B w/ KeywayReplaces: Delco 1953071, 1962567; Leece Neville76699

24-1501 Double GrooveApplication: Cummins Diesel (6cyl.) used onKenworth, Mack & Peterbilt w/ Delco 25SI, 29SI,30SI Series & Leece Neville JB Series Alternators.Dim: 1/2"W x 3 1/2"OD x 7/8"B w/ KeywayReplaces: Cummins 213326, Delco 1938553

24-1502 Double GrooveApplication: Cummins Diesel used on Freightliner &Kenworth.Dim: 1/2"W x 5"OD x 7/8"B w/ Keyway.Replaces: Freightliner 01-12929, Kenworth K187-310, and Leece Neville JB Series AlternatorsNote: Do not use with brushless alternators such asDelco 25SI

24-1503 Single GrooveApplication: Caterpillar D8, D9, D10 Tractors w/Delco 25SI Series, 24 Volt Alternators.Dim: 5/8"W x 4 1/8"OD x 7/8"B w/ KeywayReplaces: Caterpillar 4N8090, 4N8225


2-6

24-1504 Double GrooveApplication: Chevrolet & GMCTruck w/ 671 Detroit Diesel Eng.& Delco 30SI/TR Series Alt.Dim: 1/2" W x 3.0" OD x 7/8"Bw/ Keyway

24-1505 Triple GrooveApplication: Chevrolet & GMCTruck w/ Delco 27SI-Type 205Series Alternators.Dim: 1/2" W x 2.87" OD x 7/8"Bw/ KeywayReplaces: GM # 2048694

24-1506 Triple GrooveApplication: Mack Trucks w/Delco 25, 29 & 30SI Series Alt.Dim: ½ W” x 3.50" OD x 7/8"Bw/ KeywayReplaces: Mack # 310GC276

24-1508 Single GrooveApplication: Chevrolet, GMC,and Mack Trucks w/ 20 & 21SISeries AlternatorsDim: ½” W x 3.56” OD x 7/8” BReplaces: Delco # 1987932

24-1509 Double GrooveApplication: ConsolidatedDiesel, Cummins, Detroit Diesel,Ford, Mack, and Volvo White-GMC Trucks w/ Delco 21SISeries AlternatorsDim: ½” W x 3.53” OD x 7/8” BReplaces: IHC # 1687644-C1

24-1750 9-GrooveApplication: Cummins & DetroitDiesel eng., Euclid & Uni-RigEquipment w/ Delco 25 & 30SISeries AlternatorsDim: 32mm W x 2.84”OD x 7/8”BReplaces: Detroit # 5145471

24-1751 7-GrooveApplication: Chevrolet andGMC Trucks w/ Delco 20 & 21SISeries AlternatorsDim: 22mm W x 2.23”OD x 7/8”BReplaces: Delco # 10468768

24-1752 8-GrooveApplication: Ford Truck w/Delco 21, 25, 26, & 30SI SeriesAlternatorsDim: 28mm W x 3.43”OD x 7/8”BReplaces: Delco # 10468526 andFord # F0HZ-10344C, GP-674

24-1753 8-GrooveApplication: Ford Truck w/Delco 21SI Series AlternatorsDim: 28mm W x 2.76”OD x 7/8”BReplaces: Delco # 10474925 &Ford # F3HZ-10344B, GP-698

24-1754 Dual 4-GrooveApplication: Chevrolet & GMCTrucks w/ Delco 21SI Series Alt.Dim: 14mm W x 2.22”OD x 7/8”BReplaces: Delco # 10470322


2-7

24-2500 Double GrooveApplication: Ford “Blue Back” 70- 90 Amp Truck Alternators,FD5031 & FD5032Dim: 1/2" W x 3.31"OD x .880"Bw/ KeywayReplaces: C7TF-10A352A, C7TZ-10344A, E2HF-10A352AA, E2HZ-10344A, GP-484 & GP-608

24-2501 Double GrooveApplication: Ford “Humpback” 65- 90 Amp Truck Alternators,FD5014 & FD5016Dim: 3/8" W x 3.06"OD x .880”BReplaces: C7TF-10A352B, C7TZ-10344B & GP-485

24-4100 Single GrooveApplication: Thermo King w/Motorola 8HA Series Alt.

24-5500 Double GrooveApplication: Mack Trucks w/Leece Neville JB Series Alt.Dim: 1/2" W x 4.45" OD x 7/8"Bw/ KeywayReplaces: Mack # 302GC2295

24-5501 Triple GrooveApplication: Mack Trucks w/Leece Neville JB Series Alt.Dim: 1/2" W x 4.45" OD x 7/8"Bw/ KeywayReplaces: Mack # 302GC273

24-7750 8-GrooveApplication: Kenworth TrucksDim: 28mm W x 2.99”OD x 7/8”BReplaces: Kenworth # K187367


2-8

SPECIFICATIONS:

SERIES: Delco 20 SITYPE: 300GRD. POL.: NegativeAPPL.: Misc. H.D. TrucksCORE CLASS: 152

PART NO. VOLTS AMPSDR3127 12 60DR3155 24 45DR3156* 24 45DR3157 24 35DR4044* 12 60

* Indicator Terminal in place of Relay Terminal

For Your Information…

Each of our remanufactured units is packaged with a complete list of installation instruc-tions. These instructions are provided for your convenience to make certain that theremanufactured unit will function properly and to prevent needless changing of parts.

Also, Section 5 of this catalog is devoted to trouble shooting and diagnostic procedures,including diagrams and worksheets, to assist you in accurately identifying problems in thestarting and / or charging circuits. This information is also available from your local dis-tributor in wall chart form.


2-9

SPECIFICATIONS:SERIES: Delco 21SIGRD. POL.: NegativeAPPL.: Misc. H.D. TrucksCORE CLASS: 118

BATT. RELAY INDICATORPART NO. VOLT. AMPS SYST. TERM. TERM TERMDR4058 12 100 1-wire 1/4" PIN -DR4059 12 100 1-wire 5/16" - 10-24DR40605 12 125 3-wire 5/16" 10-24 -DR4061 12 100 3-wire 5/16" 10-24 -DR4062 24 70 1-wire 5/16" - 10-24DR4063 12 145 3-wire 1/4" PIN -DR4064 12 160 3-wire 5/16"2 10-243 -DR4065 12 100/115 3-wire 1/4" PIN -DR4066 12 115 1-wire 5/16" 10-24 10-24DR4067 12 130 1-wire 5/16" 10-24 10-24DR4068 24 70 3-wire M6 M4 -DR4069 12 145 3-wire 5/16" 10-24 -DR4070 12 130 1-wire 1/4" 10-24 10-24DR4071 12 65 1-wire 1/4" PIN 10-24DR4072 12 145/160 1-wire 1/4" PIN -DR4073 24 70 1-wire M6 M4 M4DR4074 12 130 1-wire 5/16" 10-24 -DR4075 12 130 1-wire 1/4" PIN 10-24DR4076 12 100 1-wire 1/4" PIN 10-24DR4078 12 115 1-wire 1/4" PIN 10-24DR4079 12 145 1-wire 1/4" PIN 10-24DR4082 12 145 1-wire 5/16" 10-24 10-24DR40896 12 100 1-wire 1/4” 10-24 10-24DR40906 12 130 1-wire 1/4“ 10-24 10-24DR40916 12 145 1-wire 1/4” 10-24 10-24DR4093 12 115/130 1-wire 1/4" PIN -DR40946 12 100 1-wire 1/4” PIN 10-24DR4105 12 100/115 1-wire 5/16" 10-24 -DR4106 12 130 1-wire 5/16" PIN -DR4107 12 160 1-wire 5/16" PIN4 -DR4109 12 160 1-wire 5/16" 10-24 10-24DR4110 12 160 3-wire 5/16" 10-24 -DR4111 12 160 3-wire 5/16"2 10-243 -DR4113 12 65 1-wire 1/4" PIN -DR4118 12 100 3-wire 5/16"2 10-243 -DR4119 12 130 3-wire 5/16"2 10-243 -

1 Universal terminal used (10-24 and pin together).2 Battery Insulator with molded cable guide.3 Relay terminal used in the I-terminal location.4 Relay terminal is disconnected in OEM #1117917.5 Includes temperature compensation regulator and debris shield.6 New style with long SRE bearing.


2-10

21SI Illustration

22SI Illustration

SPECIFICATIONS:SERIES: Delco 22SITYPE: 350 & 355POLARITY: Negative Grd.MOUNT: 3 7/8” (SAE

J180)APPL.: Misc. H.D.

TrucksCORE CLASS: 197

BATTERY RELAY IND.PART NO. VOLTS AMPS TERM. TERM. TERM.DR4020 12 100 5/16” 10-24 10-24DR4021 12 130 5/16” 10-24 10-24DR4022 12 145 5/16” 10-24 10-24


2-11

Thicker thrubolts 22SI

embossedon frame

Ground studat 4:00

Ribs onSRE Frame

Ground studat 3:00

SPECIFICATIONS:SERIES: Delco 25 SI1/ 26 SI2

TYPE: 400 & 4503

POLARITY: Positive/Negative grd.MOUNT: 3 7/8" (SAE J180)OTHER: Internal RegulatorAPPL.: Misc. H.D. TrucksCORE CLASS: 104

1 Built-in Solid State Regulator2 Built-in Integrated Circuit Regulator3 Type 450 features load dump capacity.Recommended for off-highway and marine use.Note: All 25SI and 26SI have Load DumpCapacity feature.

BATTERY RELAY/PART NOS. SERIES-TYPE VOLTS AMPS GRD. TERM. IND. TERM.1

DR3028 25SI-400 12 75 Neg. 7/16" PINDR3029 25SI-400 12 75 Pos. 7/16" PINDR3030 25SI-450 24 50 Neg. 7/16" PINDR3031 25SI-450 Superceded by DR3028DR3032 25SI-450 24 35 Neg. 7/16" PINDR30992 25SI-450 24 75 Neg. 7/16" PINDR3158 25SI-450 24 50 Neg. 7/16" 10-243

DR4053 25SI-450 32 50 Neg. 7/16” PINDR4054 25SI-450 24 50 Neg. 7/16” 10-24DR4055 25SI-450 12 85 Neg. 7/16” 10-243

DR4077 25SI-400 12 85 Neg. 7/16" PINDR4083 25SI-450 24 75 Neg. 7/16" PINDR4200 26SI-450 24 75 Neg. 7/16" PINDR4201 26SI-450 24 50 Neg. 7/16" PINDR4202 26SI-450 12 85 Neg. 1/4" PINDR4203 26SI-450 12 85 Neg. 7/16" PINDR4204 26SI-450 12 85 Neg. 7/16” 10-24DR4205 26SI-450 12 85 Neg. 7/16” 10-243

DR4206 26SI-450 24 50 Neg. 7/16” 10-243

DR4207 26SI-450 24 75 Neg. 7/16” PIN

1 Relay terminal featured unless otherwise noted2. With radio interference suppression feature3. Terminal used for Indicator Light


2-12

SPECIFICATIONS:SERIES: Delco 27SITYPE: 200, 202 & 205*POLARITY: Positive/ Negative grd.MOUNT: 3 7/8" (SAE J180)OTHER: Internal RegulatorAPPL.: Misc. H.D. TrucksCORE CLASS: 105

* Type 202 features totally encloseddesign. Type 205 features splineSRE rotor shaft for accessory drive.

PART NO. TYPE VOLTS AMPS GRD.DR3071 200 12 80 Neg.DR3086 200 12 80 Pos.DR3100 200 24 65 Neg.DR3104 202 24 30 Neg.DR3115 205 12 80 Neg.DR3116 205 12 100 Neg.DR3117 200 12 100 Neg.DR31761 200 12 65 Neg.DR3177 200 12 80 Neg.DR4084 205 12 65 Neg.

1 3-wire hookup.

SPECIFICATIONS:SERIES: Delco 29 SITYPE: 300POLARITY: Negative grd.MOUNT: 3 7/8” (SAE J180)APPL.: Misc. H.D. TrucksCORE CLASS: 153

PART NO. VOLTS AMPSDR3160 12 90DR3161 24 60


2-13

SPECIFICATIONS:SERIES: Delco 30SITYPE: 400 & 450POLARITY: Positive/Negative grd.MOUNT: 3 7/8" (SAE J180)OTHER: Brushless StyleAPPL.: Misc. H.D. TrucksCORE CLASS: 144

PART NOS. VOLTS AMPS GRD. NOTESDR3094 12 90 Neg.DR3095 12 90 Pos.DR3097 24 60 Ins.DR3098 32 60 Ins.DR4049 12 105 Pos.DR4050 32 60 Ins. DDR4051 24 100 Neg.DR4052 12 105 Neg. EDR4057 12 105 Neg.DR4080 12 105 Neg. ADR4085 24 75 Neg. BDR4086 12 105 Neg. CDR4087 12 90 Ins. DDR4088 12 90 Neg. E

All models feature load dump protection and pin stylerelay terminal unless otherwise noted.

A - 1/4-28 Relay terminalB - Protective CoatingC - Dummy Relay terminalD - Voltage adjustment providedE - 1/4-28 Indicator terminal

SPECIFICATIONS:SERIES: Delco 30 SI / TRTYPE: 450POLARITY: Positive/ Negative grd.MOUNT: 3 7/8” (SAE J180)APPL.: Misc. H.D. TrucksCORE CLASS: 144OTHER: Brushless Style. Features

24-volt starting & 12-voltlighting - no series parallelswitch needed.

PART NO. VOLTS AMPS GRD. NOTESDR3093 12 90 Neg.DR3096 12 90 Pos.DR4081 12 105 Neg.

* All models feature load dump protection.


2-14

SPECIFICATIONS:SERIES: Delco 33SITYPE: 455POLARITY: Negative grd.MOUNT: 3 7/8" (SAE J180)OTHER: Brushless Style,

Internal RegulatorAPPL.: Misc. H.D. TrucksCORE CLASS: 195

BATTERY RELAY INDICATORPART NO. VOLTS AMPS TERM. TERM. TERM.DR4001 12 110 ¼-28 10-24 10-24DR4002 12 110 ¼-28 PIN PINDR4003 12 135 ¼-28 PIN PINDR4004 12 135 ¼-28 10-24 10-24

SPECIFICATIONS:SERIES: Delco 34SITYPE: 450POLARITY: Negative grd.MOUNT: Quad 3 7/8" (SAE J180)OTHER: Brushless Style, Internal RegulatorAPPL.: Misc. H.D. TrucksCORE CLASS: 196

BATTERY RELAY INDICATORPART NO. VOLTS AMPS TERM. TERM. TERM.DR4010 12 110 ¼-28 PIN 10-24DR4011 12 135 ¼-28 PIN 10-24


2-15

Note additional mounting earfor vibration control.

SPECIFICATIONS:SERIES: Delco 40SITYPE: 150POLARITY: Negative grd.MOUNT: 3 7/8" (SAE J180)OTHER: Internal RegulatorAPPL.: Misc. H.D. TrucksCORE CLASS: 111

PART NO. VOLTS AMPSDR3042 12 105DR3043* 12 145DR3044** 12 145

* With Inverter Taps** With 3 Phase A.C. Taps


2-16

SPECIFICATIONS:SERIES: Leece NevillePOLARITY: Positive/Negative grd.MOUNT: 3 7/8" (SAE J180)OTHER: Internal RegulatorAPPL.: Misc. H.D. TrucksCORE CLASS: 109

PART NO. VOLTS AMPSLN7018 14 65LN7019 14 90LN7020 14 105LN7021 14 130LN7033 28 60LN7039 14 160LN7040 14 145LN7051 28 90

SPECIFICATIONS:SERIES: Leece NevillePOLARITY: Positive/NegativeMOUNT: Flange, 3 BoltOTHER: Internal RegulatorAPPL.: Misc. H.D. Trucks

w/ Detroit DieselCORE CLASS: 146

PART NO. VOLTS AMPSLN7029 14 75LN7030 14 100LN7031 14 130


2-17

SPECIFICATIONS:SERIES: MotorcraftVOLTS: 12POLARITY: Negative grd.MOUNT: 3" SpindleOTHER: External Regulator,

Humpback StyleAPPL.: H.D. Ford TrucksCORE CLASS: 113

PART NO. AMPSFD5014 65FD5016 90

SPECIFICATIONS:SERIES: MotorcraftVOLTS: 12POLARITY: Negative grd.MOUNT: 3" SpindleOTHER: External Regulator,

Blueback StyleAPPL.: H.D. Ford TrucksCORE CLASS: 168

PART NO. AMPSFD5031 70FD5032 90

SPECIFICATIONS:SERIES: MotorolaVOLTS: 12POLARITY: NegativeMOUNT: 1" Spindle w/ 1/2" hole.OTHER: External RegulatorAPPL.: Thermo King / Carrier TranscoldCORE CLASS: 110

PART NO. AMPS NOTESMA9028 35 Small DE Brg. Frame, 5/16" adj. holeMA9029 60 w/ Reg. attached, 3 adj. holes, 5/16" @MA9055 37 w/ Reg. attached, 3 adj. holes, 5/16" @MA9057 51 3 adj. holes, 5/16" @MA9082 35 Large DE Brg. Frame, 5/16" adj. holeMA9082A 37 Large DE Brg. Frame, 3 adj. holes, 5/16" @MA9117 37 W/ Reg. attached, 3 adj. holes, 5/16" @MA9138 55 Large DE Brg. Frame, 5/16" adj. holeMA9152 37 5/16" adj. holeMA9152A 51 5/16" adj. hole


2-18

SPECIFICATIONS:SERIES: MotorolaVOLTS: 12POLARITY: Negative grd.MOUNT: 1" Spindle w/ 1/2" hole.APPL.: Thermo King / Carrier TranscoldNOTES: All internally regulated, 14.4

volts unless otherwise noted.CORE CLASS: 186

PART NO. AMPS NOTESMA9135 37 3 adj. holes, 5/16", Field diode typeMA9147 65 3 adj. holes, 5/16", Field diode typeMA9148 37 3 adj. holes, 5/16", Field diode type,

Regulator set at 14.0 volts.MA9149 65 3 adj. holes, 5/16", Field diode type,

Regulator set at 14.0 volts.MA9151 65 3 adj. holes, 5/16", Field diode type

SPECIFICATIONS:SERIES: MotorolaAPPL.: Misc. H.D. trucksCORE CLASS: 112

PART NO. VOLTS AMPS GRD. MNTG. NOTESMA9118* 12 130 Neg. 3" Spool, Externally regulated, SRE hsg. at 6 o’clock positionMA9119* 12 90 Neg. 3" Spool, Externally regulatedMA9120* 12 130 Neg. 3" Spool, Externally regulated, SRE hsg. at 3 o’clock positionMA9122 12 90 Neg. Dual Foot (SAE J180), w/ regulator attachedMA9123 12 90 Pos. Dual Foot (SAE J180), w/ regulator attachedMA9124** 12 130 Neg. Dual Foot (SAE J180), w/ regulator attached and 3 AC terminalsMA9130 24 75 Neg. Dual Foot (SAE J180), w/ regulator attached and 3 AC terminalsMA9156 12 130 Neg./Pos. Dual Foot (SAE J180), w/ regulator attached and 3 AC terminalsMA10-254 12 160 Ins. Dual Foot (SAE J180), w/ regulator, incl. adjustable voltage feature

* Note: These models use the existing Ford regulator. To convert to a Motorola Integral regulator, usekit number MA105-277.

** Model shown.


2-19

Section3

Heavy DutySolenoids

Solenoid Rotational Instructions

The Delco 30MT, 35MT, 37MT, 40MT, 42MTand 50MT units are composed of a two piecedrive end housing which allows up to 24 pos-sible solenoid positions. First, notice that theposition of the solenoid on the unit you arereplacing. If the unit is not available, refer tothe solenoid chart for the proper degree set-ting. To rotate the housing to the correct po-sition, remove the five 7/32" and one 5/32"hex head screws and then rotate the hous-ing to the desired position and reassemblethe unit. Torque the six hex screws to 17 footpounds (Ft. Lbs.) and place the rubber plugsin the remaining unused positional holes.

Note: Short hex head screw must be replacedin the hole closest to the solenoid. The longerhex head screw will not fit in this hole

SPECIFICATIONS:SERIES: 30 MT & 35 MTCORE CLASS 135

Part Number Volts NotesSS42 12 4 Terminal,

Grounded Base

HEAVY DUTY SOLENOIDS

3-3

SPECIFICATIONS:SERIES: 37 MTCORE CLASS: 135

Part No. Volt Motor Stud Bat. Stud NoteSS3511 12 3/8" - 16 3/8" - 16 ASS3512 12 3/8" - 16 1/2" - 13 ASS3514 24 1/2" - 13 1/2" - 13 BSS15609 12 1/2" - 13 1/2" - 13 CSS15610 12 1/2" - 13 1/2" - 13 DSS15612 12 1/2" - 13 3/8" - 16 CSS15619 24 1/2" - 13 1/2" - 13 D

NOTES:A. 3 Terminal grounded baseB. 4 Terminal grounded baseC. 3 Terminal grounded base, internal threaded motor stud, and switch terminal right sideD. 3 Terminal grounded base, internal threaded motor stud, and switch terminal left side

SPECIFICATIONS:SERIES: 40MT & 50 MTCORE CLASS: 135

Early Style

Part No. Volts Notes

SS4 24 Battery stud right sideSSD6 12 Battery stud left sideSSD7 12 Battery stud right sideSSD10 24 Battery stud left side

Late Style

Part No. Volts Notes

SS3504 12 Battery stud right sideSS3505 24 Battery stud right sideSS3506 12 Battery stud left sideSS3507 24 Battery stud left sideSS3508 32 Battery stud right side


3-4

Early Style Late Style

SPECIFICATIONS:SERIES: 42 MTCORE CLASS: 135

Part No. Volts Motor Stud Bat. Stud NotesSS3513 12 1/2" - 13 1/2" - 13 ASS3515 24 1/2" - 13 1/2" - 13 ASS3519 12 1/2" - 13 1/2" - 13 B

NOTES:A. 4 Terminal grounded base.B. 4 Terminal grounded base, reverse switch and groundterminals.

LEECE NEVILLECore Class: 135

Part No. VoltsSS7500 12SS7501 24

SERIES PARALLEL SWITCHES

Part No. VoltsSSD15 12/24SSD16 12/24


3-5

SSD15 SSD16

Section4

HeavyDuty

Starters

REPLACEMENT DETERMINATION

1. Check state of battery charge.

2. Check battery connections for tight, clean connections. Be sure to check ground sidecables as well.

3. Check operation of the magnetic switch. Magnetic switch failure caused by low voltageduring cold weather may sound similar to the sound of a starter failing to stay engaged withthe engine. The cause of this is a low voltage condition releasing the electrical connection ofthe magnetic switch.

4. Check for available voltage at the starter while cranking. If the starter still cranks slow,place a voltmeter from solenoid “BAT” terminal to the starter ground terminal. If voltage is9.0 volts or less while cranking at room temperature, check connecting cables, connectionsand magnetic switch for high resistance.

5. Check interconnecting battery cables. Measure the terminal voltage of each batterywhile cranking. If there is a difference between any two battery readings in the same boxbymore than 0.5 volts, or if any connection feels warm to the touch, check, clean or replaceinterconnecting cables or ends.

Be sure to check the engine for a mechanical bind causing a slow crank.

Only after making all checks as described and vehicle still does not crank properly, replacethe starter.

HEAVY DUTY STARTERS

4-3

INSTALLATION INSTRUCTIONS

This starter may be equipped with a multipurpose drive end housing. If the replacement unitis different in appearance from the original, it may be due to improper nose housing align-ment. Normally, the nose housing position is pre-set at the factory for the model application.It is possible, however, that the nose housing position be rotated to facilitate solenoid posi-tioning for your application.

MAKE SURE THAT THE BATTERY CABLE IS DISCONNECTED FROM THE STARTERBEFORE PROCEEDING.

BATTERY:1. Make sure the battery is well charged and that all cells are in good condition (hydrometer

test suggested). The CCA rating of the batteries should be no less than original equipmentspecifications.

2. Battery posts should be clean and free of corrosion or foreign material.

CABLES:1. Cable ends at the starter, battery, solenoid and ground must be clean and tight.2. Cable terminals should be replaced if corroded or frayed cable wire is evident.3. If cable is to be replaced, use the same length, gauge, and suggested clamps as

originally specified by the manufacturer.

MOUNTING:1. In the event that the nose housing position is rotated, torque all head screws to proper

specifications. An upward solenoid mounting position is always recommended.2. Always use the correct size mounting flange bolts when installing the starter.3. Replace ring gear if badly burned or teeth are damaged.

HEAVY DUTY STARTERS

4-4

Note difference in lever housing:

Leece Neville has no plug and usesround solenoid.Prestolite has hex plug and uses “Delcostyle” solenoid.Delco 40-42MT has cross-slot plug.Delco 42MT’s solenoid mounts to leverhousing, not field barrel.

Note difference in brush covers:

Older Leece Neville has band type.Newer style has cast aluminum backcover similar to 42MT.Prestolite has no external access.Delco 40MT has cross plugs.*Delco 42MT had a cap style brushcover.

*Delco also uses rectangular brushcovers held on with 2 screws (olderunits) and a band type, usually indicat-ing CCW rotation.

HEAVY DUTY STARTERSSTARTER IDENTFICATION AIDS

4-5

40 MTOld StyleSolenoid

40MTNewStyleSolenoid

42 MT

Prestolite

Leece Neville (older style) Leece Neville (w/cast alum. cover plate)

Note hexplug

HEAVY DUTY STARTERS

4-6

Any Motor Model May Have Combinations of These Features

FEATURE IDENTIFICATION

SPECIFICATIONS:SERIES: Delco 27MTVOLTS: 12FIELD CASE: 6 3/4" Step Down or StraightROTATION: Clockwise (CW)CORE CLASS: 158

Part No. Mount Application Comments

3300S 3 Hole Flange 6.9L Ford, early Old # STD38943764S* Offset Pad 6.2L GMC Old # STD3887

* Shown

SPECIFICATIONS:SERIES: Delco 28 MTFIELD CASE: Gear ReductionROTATION: Clockwise (CW)CORE CLASS: 122

Part No. Volts Tth. Mount ApplicationSTD3926 12 10 Offset Pad Chev./GMC 6.2L,6.5L Diesel w/ATSTD3927* 12 10 Offset Pad Chev./GMC 6.2L,6.5L Diesel w/MTSTD4313 12 10 Flange Cummins Engine, Ford 6.9 DieselSTD4318 12 10 Flange Bluebird bus, Ford (dry clutch)STD4319 12 10 Flange Ford Truck. (wet clutch)STD4321 12 10 Flange Champion w/Cummins B seriesSTD4322 12 10 Flange Consolidated Diesel, CumminsSTD4323 24 10 Flange Cummins EngineSTD4325 24 10 Flange Detroit DieselSTD4342 12 10 Flange Mack Truck (Midliner models)

*shown

HEAVY DUTY STARTERS

4-7

SPECIFICATIONSSERIES: Delco 30MTVOLTS: 12ROTATION: ClockwiseFIELD CASE: 7" - 7 3/8"MOUNT: Flange, 3 boltAPPLICATION: Medium TrucksCORE CLASS: 159

Part No. Solenoid Drv. Tth. CommentsSTD454 SS42 9 Internal .42" mtg. holes.STD455 SS42 9 Internal special D.E. housing.STD456 SS42 9 External .42" mtg. holes.STT7086 SS42 12 Internal .66" mtg. holes.STT7242 SS42 12 External .66" mtg. holes.

SPECIFICATIONS:SERIES: Delco 35MTROTATION: ClockwiseFIELD CASE: 8" - 9 1/4"MOUNT: Flange, 3 boltAPPLICATION: Medium TrucksCORE CLASS: 140

Part No. Volts Solenoid Drv. Tth. CommentsSTD415 12 SS42 10 Internal .42" mtg. holes off ctr.STD429 12 SS42 10 Internal, .42" mtg. holes off ctr.

inside nose rotated 20°STT7179 12 SS42 12 Internal .42" mtg. holes off ctr.STT7217 24 SS4 12 External

HEAVY DUTY STARTERS

4-8

Internal External

Internal External

SPECIFICATIONS:SERIES: Delco 37 MTMOUNT: FlangeAPPLICATION: Medium - H.D.SOLENOID: See BelowCORE CLASS: 161FIELD CASE: 6 1/2”

Part No. Volts Rtn. Solenoid Drv.Tth. Mtg. NotesSTT7264 12 CW SS3511 10 .53STT7268 24 CW SS3514 12 .66 Special CE frameSTT7270 12 CW SS3516 10 .66 Mtg. register offset from motor center,

shielded solenoid w/ silver studsSTT7295 12 CW SS3512 10 .66 Frame ground stud includedSTT7297 12 CW SS15609 12 .53STT7298 12 CW SS15609 10 .66STT7299 12 CW SS15610 10 .66STT7413 12 CW SS15609 12 .66 DE housing adjusting holes are 7.5°

CCW from standardSTT7420 12 CW SS15609 12 .66 Frame ground stud includedSTT7426 12 CW SS15609 12 .66 DE housing adjusting holes are 7.5°

CCW from standardSTT7435 12 CW SS15609 10 .41 CE frame w/ ground stud hole, not

used, 2150 flywheel openingSTT7436 12 CW SS15609 12 .53 Frame ground stud includedSTT7437 12 CW SS15618 12 .53 CE ground stud included w/ over crank

protectionSTT7438 12 CW SS15618 12 .53 CE ground stud included, 4 terminal

sol.STT7446 12 CW SS15609 10 .41 CE frame rotated 180° w/ grd. terminal

& 215° flywheel openingSTT7447 12 CW SS15623 11 .53 High wedge sol. cap., L.H. terminal is

dummySTT7453 12 CW SS15609 10 .41STT7456 12 CW SS15618 10 .41 w/OCP & frame ground studSTT7469 12 CW SS15618 10 .41 w/OCP & frame ground stud

HEAVY DUTY STARTERS

4-9

DELCO 40 MT

OCP FEATURE

DEH View

40 MT TYPEWith late model solenoid

Completely interchangeable with early modelsolenoid.

DELCO 40 MTPOPULAR DRIVE END HOUSINGFLYWHEEL MTG.OPENING HOLE180° DIAM. .66"

40 MT TYPEWith early model switch

HEAVY DUTY STARTERS

4-10

DEH view

SPECIFICATIONS:SERIES: Delco 40MTCASE: 10" length, 5" diameter field caseSOLENOID: See belowMOUNT: Flange, multi-position Drive End housingAPPLICATION: Misc. H.D. trucksCORE CLASS: 128 / 165 (see below)

Part No. Voltage Rtn. Solenoid Drv. Tth. Core Class NotesSTD384 24 CW SS4 11 128STD407 12 CW SSD6 13 128STD408 12 CW SSD7 11 128STD410 12 CW SSD7 11 128STD411 12 CW SSD7 11 128 145° Flywheel openingSTD416 24 CW SS4 11 128 .53" DE Mounting holesSTD435 12 CW SSD7 12 128STD438 12 CW SSD6 12 128STD439 12 CW SSD7 13 128STD442 24 CW SS4 12 128STD458 12 CW SSD6 11 128STD461 12 CW SSD6 12 128STD462 12 CW SSD7 11 128 CE stud reversedSTD466 24 CW SSD10 11 128STD480 24 CW SS3505 12 128 145° Flywheel openingSTD481 12 CW SS3504 12 128 145° Flywheel openingSTD482 12 CW SS3504 11 128 With OCP featureSTD483 12 CW SS3504 11 128 With OCP feature, 145° Flywheel openingSTD484 12 CW SS3504 12 128 With OCP featureSTT7131 12 CW SSD7 12 128 .53 DE mounting holesSTT7133 24 CW SS4 13 128STT7144 12 CCW SSD7 11R 165STT7145 12 CCW SSD6 11R 165 Scalloped LH & 145° Flywheel openingSTT7151 12 CW SSD6 12 128 .53" DE Mounting HolesSTT7219 24 CW SSD10 12 128 .53" DE Mounting HolesSTT7220 12 CW SS3506 11 128STT7221 24 CW SS4 12 128 Offset L.H. .53" DE Mounting HolesSTT7292 24 CCW SSD10 11R 165 145° Flywheel opening

HEAVY DUTY STARTERS

4-11

with new style solenoid with old style solenoid

SPECIFICATIONS:SERIES: Delco 42MTFIELD CASE: 7 3/8" length, 5 1/2" diameterSOLENOID: See BelowMOUNT: Flange, multi-position Drive

End housing*APPLICATION: Misc. H.D. trucksCORE CLASS: 162 / 193 (see below)

* All mounting holes are .66 unlessotherwise noted.

Part No. Voltage Rtn. Solenoid Dr. Tth. Core Class NotesSTT7276 12 CW SS3513 11 162STT7277 Use: STT7276STT7278 12 CW SS3513 12 162 145° DE hsg.STT7279 24 CW SS3515 12 162 145° DE hsg.STT7281 12 CW SS3513 12 162STT7282 24 CW SS3515 12 162STT7283 24 CW SS3515 12 162 Special CE frameSTT7284 24 CW SS3515 11 162STT7285 Use: STT7281STT7286 Use: STT7282STT7287 Use: STT7284STT7288 12 CW SS3513 13 162STT7289 12 CW SS3513 12 162 24 position D.E. housing usedSTT7293 12 CW SS3519 12 162 Solenoid terminals reversedSTT7296 12 CW SS3513 11 162 Replaces STT7280 and STT7291STT7425 24 CW SS3515 13 162STT7430 12 CW SS3513 11 162 24 Position DE hsg. std. w/ OCPSTT7431 12 CW SS3513 11 162 12 Position DE hsg. std. w/ OCPSTT7432 12 CW SS3513 11 162 24 Position 145° DE hsgSTT7433 24 CW SS15625 12 162 .53 DE mounting holes, Shielded Sol.STT7439 12 CW SS15602 12 162 Solenoid w/ 24V (silver) studs, w/ OCPSTT7440 12 CW SS3513 12 162 .53 DE mounting holesSTT7441 12 CW SS3513 12 162 .53 DE mtg. holes, CE rotated 180°, w/ OCPSTT7442 12 CW SS15602 11 162 Solenoid w/ 24v (silver) studs, w/ OCPSTT7443 12 CW SS3519 12 162 Solenoid terminals reversed, w/ OCPSTT7450 12 CW SS3519 12 162 .53 mtg. Holes, Sol. term. reversedSTT7457 24 CCW SS15597 11R 193 145° DE hsg., Sol. term. reversedSTT7458 24 CCW SS15597 11R 193 Solenoid terminals reversedSTT7459 24 CCW SS15597 11R 193 Sol. term. reversed, w/ OCPSTT7460 24 CCW SS15597 11R 193 Sol. term. rev., CE rotated 180°, w/ OCPSTT7462 12 CW SS15645 11 162 w/ Integral Magnetic switchSTT7463 12 CW SS15645 11 162 w/ Integral Magnetic switch & OCPSTT7464 12 CW SS15645 12 162 w/ Integral Magnetic switchSTT7465 12 CW SS15645 12 162 w/ Integral Magnetic switch & OCPSTT7466 12 CW SS15645 12 162 w/ Integral Magnetic switch & 145° DE hsg.

STT7467 12 CW SS15645 12 162 w/ IMS, OCP, & 145° DE hsg.STT7468 24 CCW SS3515 11 193 w/ 24 position DE hsg.

HEAVY DUTY STARTERS

4-12

SPECIFICATIONS:SERIES: Delco 50MT*CASE: 10 1/4" length, 5 1/2" diameterSOLENOID: See BelowMOUNT: Flange, multi-position Drive End

housing.APPLICATION: Misc. H.D. trucks and construction

equipmentCORE CLASS: 147

* This unit has six sets ofpole shoe screws (2 ea. set),indicating six field design.

Part No. Volts Rtn. Solenoid Dr.Tth. Notes

STD440 24 CW SS4 11 145° Flywheel openingSTD441 24 CW SS4 11 Long style DE w/ 145° opening,STT7013 24 CW SS4 11STT7160 24 CW SS4 11 32 volt field coilsSTT7161 24 CW SS4 12 Long style DE w/ 215° opening, 32 volt field coilsSTT7224 12 CW SSD7 11STT7225 24 CW SSD10 11STT7226 24 CW SS3505 12 Offset LHSTT7227 24 CW SS3505 11 215° Flywheel opening, 32 volt field coilsSTT7228 24 CW SS4 11 Special DE housing mounting holesSTT7229 32 CW SS3508 11

DELCO 50 MT DRIVE END HOUSINGS

LONG STYLE

Drive End Housing View (145° style)

SHORT STYLE

Drive End Housing View (180° style)

HEAVY DUTY STARTERS

4-13

SPECIFICATIONS:SERIES: Leece Neville MEAPPLICATION: Misc. H.D. trucksCORE CLASS: 124

* All with .66 mounting holes unless otherwise noted.

Part No. Voltage Rtn. Solenoid Dr.Tth. Notes

STN7810 12 CW SS 7500 11STN7811 12 CW SS 7500 12 .53 DE mounting holes

STN7812 12 CW SS 7500 12STN7813 12 CW SS 7500 13

SPECIFICATIONS:SERIES: Leece NevilleAPPLICATION: Misc. H.D. trucksCORE CLASS: 129

* All with .66 mounting holes unless otherwisenoted.

Part No. Voltage Rtn. Solenoid Dr.Tth. NotesSTN7600 12 CW SS7500 11 Long Frame Motor, Delco 50MT replacementSTN7800 12 CW SS7500 11STN7801 24 CW SS7501 11STN7802 24 CW SS7501 11 Long Frame Motor, Delco 50MT replacementSTN7803 12 CW SS7500 12 .53 DE mounting holesSTN7804 24 CW SS7501 11 Long frame motor, Cat. Application, special long

DE hsg. and driveSTN7805 12 CW SS7500 12STN7806 12 CW SS7500 13STN7807 12 CW SS7500 12 DE hsg. w/ 145° opening

HEAVY DUTY STARTERS

4-14

Note: Aluminum brushholder cover

Note: Band over brushholder

SPECIFICATIONS:SERIES: PrestoliteAPPLICATION: Misc. H.D. trucksCORE CLASS: 145

Part No. Voltage Rtn. Solenoid Dr.Tth. Mtg. Notes

STA1809 12 CW SSD7 12 .66 Original Solenoid replaced with Delco styleSTA1810 12 CW SSD7 11 .66 Original Solenoid replaced with Delco style

HEAVY DUTY STARTERS

4-15

Note: Hex head plug

Ford/Mitsubishi Gear Reduction Type Starters

SERIES: MitsubishiROTATION: ClockwiseMOUNT: Flange MountAPPLICATION: Ford 6.9L, 7.3L (Diesel)CORE CLASS: 187PART NUMBER: STJ18078

STJ18079STJ18226 (w/open DE housing)STJ18227 (w/open DE housing)

Thermo King Gear Reduction Starters

Hitachi Type Denso Type

SERIES: Hitachi SERIES: DensoVOLTS: 12 VOLTS: 12ROTATION: Clockwise ROTATION: ClockwiseMOUNT: 2 Bolt Flange MOUNT: 2 Bolt FlangeAPPLICATION: Late model Thermo King APPLICATION: Late model ThermoSTYLE: Gear reduction King, replacement forCORE CLASS: 134 O.E.M. model; Carrier

TranscoldPART NUMBER: STJ18084, STJ18159 STYLE: Gear reduction

CORE CLASS: 134PART NUMBER: STJ18074, STJ18155,

STJ18158, STJ18166,STJ18168, STJ18169,STJ18197, STJ18220,STJ18224

HEAVY DUTY STARTERS

4-16

Section5

Heavy DutyVehicle

Wiring SystemChecks

SYMPTOM

Starter drags, slow, sluggish cranking

Solenoid chatters, won’t engage starter drive

Starter fails to operate at all

Starter spins but won’t engage flywheel

Starter will not disengage

Batteries won’t stay up, won’t hold a charge,low output from alternator

Alternator doesn’t charge

Alternator won’t charge at low RPM

Alternator overcharge condition

Noisy alternator

CAUSE

Weak or discharged batteryLoose or dirty connectionsCorroded or damaged cablesBad ground connection

Weak or discharged batteryLoose or dirty connectionsProblems in control circuit or magnetic switch

Dead batteryOpen wiring in starter circuitFaulty ignition switchBad solenoidProblem with starter relay

Worn or damaged ring gearIncorrect replacement starter, either wrong mounting holesize in D.E. housing or wrong starter drive

Bad ring gearStarter loose on mountingFaulty ignition switchProblem with starter relay or solenoid

Weak or discharged battery(s), bad cell or cells in batteryLoose or dirty connectionsCorroded or damaged cablesBad ground connectionLoose or worn out belts or pulley

Loose or dirty connectionsCorroded or damaged cablesBad ground connectionLoose or worn out beltsWorn pulleyAlternator rotor has lost residual magnetism, energize asper installation instructions

Loose or worn out beltsWrong pulley, causes alternator to spin too slowly at lowengine RPM

Weak or discharged battery or batteriesBad cell(s) in batteryFailed regulator

Worn or frayed beltLoose alternator mountingLoose fan and pulley assemblyWorn out bearing

QUICK REFERENCE TROUBLE SHOOTING GUIDE

5-3

DIAGNOSTIC PROCEDURE

The purpose of this section is to provide a procedure that can be used for either preventive maintenance ortroubleshooting of heavy duty vehicle electrical system. Because of vibration, corrosion, temperaturechanges, or damage, wiring and connections can deteriorate — often so slowly the operator is not aware of it.Defective wiring and connections often cause problems in starter and alternator operation.

FOUR CIRCUITS THAT NEED TO BE CHECKED:1. Cranking CircuitThis consists of the large cables that carry the high starter current. Excessive loss here causes slow crank-ing speeds - especially in cold weather. Inability to start from slow cranking can lead to starter burn-up ifcranked over 30 seconds.

NOTE: In section 1(A) the allowable maximum cable loss listed for in-service vehicles is somewhat higherthan for new vehicles, due to normal deterioration of connections. The allowable maximum cable loss asshown, covers High Output 12V starters used on most large highway diesel vehicles.Consult starter manufacturer for allowable cable loss for Standard Output or extra-large starters.

2. Solenoid CircuitThis consists of the wiring from the battery through a push button or a magnetic switch to the “SW” terminalof the starter solenoid and back to the battery. Excessive loss here can cause the solenoid to shift in and outresulting in a “no-start” condition. Burned contact disc and terminals in the starter solenoid can result. Deeplydischarged batteries can cause the same problems.

3. Control Circuit - (used with magnetic switch)This consists of wiring from the battery through a key switch and/or start button to the coil of the magneticswitch and back to the battery. Excessive loss here can cause a “no-start” complaint. Excessive loss and/ora deeply discharged battery can cause the magnetic switch to open and close; which will cause the startersolenoid to shift in and out.

4. Charging CircuitThis consists of the wiring between the alternator and the battery and return back to the alternator. Excessiveloss here can cause the batteries not to charge properly. Discharged batteries can cause the problemsoutlined above.

The procedures in Section 1(A) thru 4(b) check for excessive wiring or connection resistance by measuringthe voltage loss (drop) when a fixed current is flowing.

TEST EQUIPMENT1. Variable carbon-pile load tester 500 amp minimum with ammeter.2. Separate voltmeter - digital preferred. Capable of reading 0.1 volt increments.3. Inductive (clamp-on) ammeter - for quick, easy alternator output check.

IMPORTANT it is necessary to follow all of the steps in the listed order to prevent unnecessary removal ofstarter, alternator, or batteries.

PRECAUTIONS1. Make sure transmission is in neutral.2. Set parking brake firmly.3. Wear face or eye protection around batteries.

STARTING/CHARGING SYSTEMS CHECKS

5-4

BEGIN - CHECK BATTERIES FIRST1. Disconnect all battery terminals.2. Clean all battery terminals to bright metal3. Individually load test each battery per manufacturer ’s instructions. Use terminal adapters if

necessary.4. Replace any battery not passing load test.5. If battery is alright, continue to section 1(A).

TO CORRECT EXCESSIVE LOSSESAfter you have determined a circuit has too much voltage drop:

1. Wire brush all circuit connections.2. Tighten all electrical connections to specifications.3. If still too much loss, replace wiring with new wire of the same size (or larger). Loss can also be

reduced by paralleling another wire beside the first one with ends connected to the same points.4. During, or right after cranking, check for loose or defective cables between batteries by carefully

feeling cables between batteries and/or connections for excessive heat.


5-5

Section 1A

SECTION 1 (A)SLOW SLUGGISH CRANKING

Tighten “cable” nuts at starter.Connect load and meter V1 - battery voltage.Re-connect batteries.

TURN LOAD TO 500 AMPS; READ BATTERY VOLTAGE - V1Turn load off.Move meter to V 2 - Starter terminals only.

AGAIN TURN LOAD TO 500 AMPS; READ STARTER VOLTAGE - V2Turn load off.

CHECKBattery minus Starter equals CableVoltage Voltage Loss

v.1 - v.2 = v.3

Typical Heavy Duty High Output Starter.0.5 volt maximum loss (vehicle in service).0.375 volt maximum loss (new vehicle)Contact the manufacturer of your starter for exact cable drop values.See TMC Practice RP-105 for further information.If not ok, continue to 1(B).If ok, disconnect load tester and proceed to 2(A).

5-6

Section 1B

POSITIVE AND NEGATIVE CABLE TEST

SECTION 1 (B)TO FIND LOSS

Connect meter V 4 (positive voltage loss) using starter terminals - not load clamps.Use digital or low scale voltmeter.

Turn Load To 500 Amps Read Positive Loss V 4Turn load off

CHECKPositive plus Starter equals TotalCable Loss Loss

v.(4) + v.(5) = v.(3)

From example in 1(A).Repair or replace the cable circuit with excessive loss.NOTE: For Dual Path Circuit (Two Battery Boxes) use 250 Amp Carbon Pile Load and test each sideseparately, with other side disconnected. Allowable voltage loss is the same as for single path.

5-7

Section 2A

SECTION 2 (A): STARTER SHIFTS IN AND OUT OR WILL NOT PULL INDisconnect SW Terminal

Connect load tester and meter V 6 to measure starter cable voltage.Push Start Button

Magnetic switch should close.Slowly adjust load to 80 amps.

Read Cable Voltage - V 6Release start button.Move meter to V 7 - solenoid voltage.

Push Start ButtonSlowly readjust load to 80 amps.

Read Solenoid Voltage - V 7Release start button.

CHECKCable minus Solenoid equals CircuitVoltage Voltage Loss

v.(6) - v.(7) = v.(8)

1.0 volts maximum.If ok, turn load off, disconnect and proceed to 3(A).

5-8

Section 2B

SECTION 2 (B): TO FIND LOSSLeave load turned on.Connect meter V 9 to measure first wire loss.Use digital voltmeter or 0-3v. scale meter.If meter reads voltage, use other large terminal of the magnetic switch.

Push Start ButtonSlowly adjust load to 80 amps.

Read First Wire Loss - V 9Release start button.Move meter to V 10 to measure second wire loss. Use large terminal at the magnetic switch not usedabove.

Push Start ButtonSlowly readjust load to 80 amps.

Read Second Wire Loss - V 10Release start button.Turn load off and disconnect.

CHECKCircuit minus First Cable minus Second Cable equals MagneticLoss* Loss Loss Switchv.(8) - v.(9) - v.(10) = v.(11)

1.0v. max. 0.4v. max. 0.4v. max. 0.2v. max.

*from section 2(a)Repair or replace cable(s) or magnetic switch with excessive losses.If ok, turn load off, disconnect and proceed to 3(A).

5-9

Section 3A

SECTION 3 (A): MAGNETIC SWITCH WILL NOT CLOSE OR DROPS OUT TOO SOONLeave Switch Terminal Disconnected

Connect meter V 12 to measure cable voltage. Turn ignition on.Push Start ButtonRead Cable Voltage - V 12

Release start button.Move meter to V 13 to measure magnetic switch coil voltage.

Push Starter ButtonRead Switch Voltage - V 13

Release start button.

CHECKCable minus Switch equals CircuitVoltage Voltage Lossv.(12) - v.(13) = v.(14) / 0.5v. max.

If circuit loss is 0.5v. or less and magnetic switch closes — re-connect switch terminal, end test andproceed to alternator wiring test 4(A).If circuit loss is 0.5v. or less but magnetic switch does not close — replace magnetic switch and repeatabove test.If circuit loss is more than 0.5v. — continue to 3(B).

5-10

Section 3B

CONTROL CIRCUIT TEST (individual segments)

SECTION 3 (B): TO FIND LOSSUse digital meter or 0-3v. scale meter.Connect meter V 15 — solenoid to ignition.

Push Start Button - Read V 15Release start button.

Repeat for Other Circuit Parts

CHECKa. Solenoid to ignition v.(15)b. Ignition switch v.(16)c. Ignition to start switch v.(17)d. Start switch v.(18)

(push switch before connecting meter)e. Start switch to magnetic switch v.(19)f. Magnetic switch to starter ground v.(20)

TOTAL LOSS (0.5V. max.)

Correct the defective part of the circuit.If the vehicle does not crank properly after checking wiring, problem is in starter or the engine itself.If necessary, replace starter.

5-11

Section 4A

SECTION 4 (A): ALTERNATOR SYSTEM WIRINGWithout Engine Running

Connect load to alternator output terminal.CAUTION: Output terminal is battery voltage.Some may require a special terminal adapter.Connect meter V 21 to batteries.

Adjust LoadTo alternator rated output.

Read Battery Voltage - V 21Turn load off.Move meter to V 22 — alternator output terminal — not load clamp.


Read Alternator Voltage - V 22Turn load off

CHECKBattery minus Alternator equals CircuitVoltage Voltage Lossv.(21) - v.(22) = v.(23) / (0.5v. max.)

If wiring is not ok, continue to 4(B).If wiring is ok, disconnect tester and go home!Check alternator and belts if problem still exists.

5-12

Section 4B

SECTION 4 (B): TO FIND LOSSConnect meter to V 24 to measure positive circuit loss.


Read Positive Circuit Loss - V 24Turn load off.Move meter to V 25 to measure negative circuit loss.


Read Negative Circuit Loss - V 25Turn load off

CHECKPositive plus Negative equals SystemCircuit Loss Circuit Loss Lossv.(24) + v.(25) = v.(23) / 0.5v. max.

Repair or replace circuit with excessive loss.Check alternator and belts if problem continues after wiring has been corrected.

5-13

SECTION 4(C)

SECTION 4(C)FINALLY - CHECK ALTERNATOR ITSELF

1. Tighten all mounting bolts and adjust belt(s).Belt Tension:a. 100 ft. lbs. for new belts.b. 85 to 90 ft. lbs. for used belts.

2. Connect a carbon pile with ammeter and voltmeter across batteries. An induction pick-up for theammeter is clamped around the alternator output cable.

3. With no electrical load on, speed up engine and check voltage. Voltage should not exceed 15 voltsafter 1 or 2 minutes of operation. If higher than 15 volts, replace alternator.

4. Speed up engine and turn carbon pile for maximum alternator output. Rated output is stamped onalternator case or label. If maximum output measured is not within 10% of rating, replace alternator,and repeat output check.

5-14

SERIES-PARALLEL SWITCH TROUBLE SHOOTING

IntroductionThe following is offered to provide information on the operation of the Series-parallel switch and its applica-

tions. This also provides service information on the most common problems that might confront the user whenservicing or troubleshooting the Series-parallel switch.

Switch OperationThree types of circuits are most commonly being used by vehicle manufacturers. They will be called “A”

circuit, “B” circuit, and Combined Series-Parallel and Magnetic Switch Circuit.To identify each, the “A” Circuit has the “A” (accessory) battery connected to the #1 terminal of the switch.

Also, if #1 terminal of the switch has more than one lead, an “A” Circuit is indicated. If the #2 terminal of theswitch has more than one lead, a “B” Circuit is indicated.

The Combined Series-Parallel & Magnetic Switch can be identified by four large terminals the same size asterminals #1 and #2 shown in the following diagrams (pages 5-33 to 5-35).

The leads at #6 and #7 terminals on all circuits may be reversed and will not affect operation.

“A” CIRCUIT - CHARGING - #SSD15 - including COMBINED SERIES PARALLEL & MAG-NETIC SWITCH CIRCUIT (Mack Truck - #SSD16):

When the series-parallel switch is in the charging or disengaged position and the engine and generator arein operation, current from the generator will flow to the #1 terminal of the series-parallel switch. At this point, thecurrent will divide with approximately half going through the “A” battery ground and back to the generator. Theremaining half will pass through the contact points between #1 and #3 terminals through the “B” battery and thecontact points between the #2 and #5 terminals to ground and back to the generator. Current is thereby pro-vided for both batteries at the generator system voltage.

“A” CIRCUIT - CRANKING - #SSD15:When the series-parallel switch is energized by closing the switch coil (terminal #7), the switch plunger is

moved into the core by the magnetic force of the coil, which causes three distinct operational steps to occur:Step one, the normally closed points between terminals #1 & #3 and terminals #2 & #5 are opened by the

moving plunger.

Step two, the large contact disc between terminals #1 and #2 is moved into contact with these terminals bythe plunger, as it continues to move.

Step three, the moving plunger closes the normally open points between terminals #4 and #5. In someinstances, due to manufacturing tolerances, the second and third steps may be reversed in their order ofoccurrence.

The above sequence takes place very rapidly. With the series-parallel switch in the described position,cranking occurs. The batteries are electrically connected in series to provide approximately double the charg-ing and accessory system voltage for cranking.

“A” and “B” batteries are placed in series by the large contact disc connecting terminals #1 and #2 together.Current from both batteries in series will flow to the end terminal of the motor and from here, it will divide in itstravel through the motor to the frame terminal. From here it will enter the “MOT” terminal of the solenoid andtravel through the “pull-in” coil of the solenoid on the “SW” terminal of the solenoid. The other part of the currentwill travel from the end terminal of the motor to the “GRD” terminal of the solenoid. From here it will flowthrough the “hold-in” coil of the solenoid and continue to the “SW” terminal of the solenoid. This total solenoidcurrent then flows through the closed contact points between terminals #4 and #5 and on to ground. Current


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traveling through ground then continues its flow to the “BAT” terminal of the solenoid and from here it completes

“A” CIRCUIT - CRANKING - #SSD 15 (cont.)

its circuit to the “A” and “B” batteries which are the source of power.

This energizing of the solenoid will pull the drive pinion into mesh with the ring gear of the engine and closethe circuit between the “BAT” and “MOT” terminals of the solenoid, thereby providing the full voltage of bothbatteries to be in series with the cranking motor. Cranking of the engine then takes place and when the startingswitch is opened the series-parallel switch returns to its charging, or disengaged position.

COMBINED SERIES - PARALLEL & MAGNETIC SWITCH CIRCUIT - (MACK TRUCK CIRCUIT)CRANKING - #SSD16:

When the series-parallel switch is energized by closing the switch to the switch coil (terminal #7), the switchplunger is moved into the core by the magnetic force of the coil, which causes two distinct operational steps tooccur:

Step one, the normally closed points between terminals #1 & #3 and terminals #2 & #5 are opened by themoving plunger.

Step two, the two large contact discs between terminals #1 and #2, #3 and #4 are moved into contact withthese terminals by the plunger as it continues to move.

The above sequence takes place very rapidly. With the series-parallel switch in the described position,cranking occurs. The batteries are electrically connected in series to provide approximately double the charg-ing and accessory system voltage for cranking.

“A” and “B” batteries are placed in series by the large contact disc connecting terminals #1 and #2 together,and #3 and #4 terminals together. Current from both batteries in series will flow to the “BAT” terminal of thesolenoid, and from here, it will travel to the cranking motor solenoid switch terminal. Part of the current willtravel through the solenoid pull-in winding to the “MOT” terminal of the solenoid, and travel through the crankingmotor circuit to the end terminal of the cranking motor and back to the “A” battery.

The other part of the current will travel through the hold-in winding out the “GRD” terminal to the endterminal of the cranking motor and back to the “A” battery. This energizing of the solenoid will pull the drivepinion into mesh with the ring gear of the engine and close the circuit between the “BAT” and “MOT terminals ofthe solenoid, thereby providing the full voltage of both batteries to be in series with the cranking motor. Crank-ing of the engine then takes place and when the starting switch is opened, the series-parallel switch returns to itscharging or disengaged position.

“B” CIRCUIT - CHARGING - #SSD15:When the series-parallel switch is in the charging position, and the engine and generator are in operation,

current from the generator will flow to the #2 terminal of the series- parallel switch.

At this point, current will divide, with approximately half going through the “A” battery to ground, and back tothe generator.

The remaining half will pass through the contact points between the #2 and #5 terminals through the “B”battery and the contacts between the #1 and #3 terminals to ground, and back to the generator. Current isthereby provided for both batteries at the generator system voltage.


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“B” CIRCUIT - CRANKING - #SSD15:When the series-parallel switch is energized by closing the switch to the switch coil (terminal #7), the switch

plunger is moved into the core by the magnetic force of the coil, which causes three distinct operational steps tooccur:

Step one, the normally closed points between terminals #1 and #3, and terminals #2 and #5 are opened bythe moving plunger.

Step two, the large contact disc between terminals #1 and #2 moves into contact with these terminals by theplunger, as it continues to move.

Step three, the normally open points between terminals #4 and #5 are closed by the moving plunger. Insome instances, due to manufacturing tolerances, the second and third steps may be reversed in their order ofoccurrence.

The above sequence takes place very rapidly. With the series-parallel switch in the described position,cranking occurs. The batteries are electrically connected in series, to provide approximately double the charg-ing and accessory system voltage for cranking.

“A” and “B” batteries, which are placed in series by the large contact between terminals #1 and #2, willprovide current flow to the “BAT” terminal of the solenoid. From this point, it will travel through the contactpoints between terminals #3 and #4 to the “SW” terminal of the solenoid. Current will continue its flow throughthe “hold-in” and “pull-in” coils of the solenoid to the “GRD” terminal of the solenoid and the frame terminal ofthe motor and on to the “A” and “B” batteries, which are the source of current. This energizing of the solenoidwill pull the drive pinion into mesh with the ring gear of the engine and close the circuit between the “BAT” and“MOT” terminals of the solenoid, thereby providing the full voltage of both batteries to be in series with thecranking motor. Cranking of the engine then takes place and when the starting switch is opened, the series-parallel switch returns to its charging position.

SERVICE PROBLEMS

The following chart on page 5-18 summarizes some of the more common service problems encountered onthe series-parallel switch. Information giving a more complete explanation of the service problems and theirsolution follows the summary.

WATER ENTRY INTO THE SWITCHMounting conditions of switches are often such that the switch is exposed to road splash. Water entry into theswitch interior can cause corrosion, icing, or unwanted electrical connections. Make sure all gaskets are tightlyseated and the switch is sealed from water entry.


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SYMPTOM CAUSE REMEDY

Corrosion in switch Water Entry Make sure switch gasket seals properly.

Blown fuse or circuit A. Under capacity fuse or breaker A. Use proper fuse or circuit breakerbreaker B. Pinion and ring gear tooth B. Replace burred pinion or ring gear.

abutmentC. Grounded motor C. Repair motorD. Defective wiring or circuitry D. Correct circuit and replace wire

Oscillating solenoid and A. Low battery A. If battery is worn out replace. Ifburned contacts battery is good, but discharged,

charge battery and determine why itdischarged

B. Resistance in wiring B. Remove resistance from controland crank circuit

C. Defective solenoid C. Replace solenoid

Both “A” and “B” batteries A. Low regulator setting A. Adjust regulatorundercharged B. Faulty generator B. Repair generator

C. Faulty wiring C. Repair wiringD. Faulty regulator D. Repair regulatorE. Under-capacity generator E. Replace with extra output generator

Battery “B” undercharged Excessive resistance in “B” battery Remove resistancecircuit

Burned or melted circuits A. No circuit breakers in #3 or #5 A. Install circuit breakersinside switch circuits.

B. Circuit breaker rating too high B. Install proper breakerC. Circuit breakers improperly wired C. Rewire circuit breaker to proper

circuit


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BLOWN FUSE OR OPEN CIRCUIT BREAKERSSome complaints of blown fuses or open circuit breakers have been received. This can result from the follow-ing:

A. Under capacity fuses or circuit breakers —

Fuses or circuit breakers, when used should be located in the system as shown on the various diagrams.Minimum fuse rating should be either 60 amperes or 55% of rated generator output — whichever is the greater.Minimum circuit breaker rating should be 40 amperes or 55% of rated generator output, whichever is greater.

Delco Remy no longer recommends the use of fuses in series-parallel circuits. The use of circuit breakersis now recommended. Reasons for this recommendation will be explained in more detail in appropriate placesin the following write-up.

B. Pinion and ring gear tooth abutment —

On solenoid operated cranking motors using the heavy-duty sprag clutch, or the Positork drive, tooth abut-ment will not permit the “BAT” and “MOT” contact to be made. However, coil current for the solenoid will flowand if kept in this position for an excessive period of time, the fuse may blow or circuit breaker open up (in circuitat the #5 terminal of series-parallel switch in Diagrams A and B). Burred ring or pinion gear teeth may becausing this abutment problem and it would be wise to correct this condition if it exists.

Since fuses have a very short time lag before blowing, when their rating is exceeded, they are no longerrecommended for use in series-parallel circuits. Tooth abutment can be expected to occur occasionally, eventhough the pinion and ring gears are in good order and not badly burred.

If the starting switch is held for a slightly extended period of time under these conditions the fuse might blow,whereas the circuit breaker would not open up. In the event that the circuit breaker does open up, under theseconditions it would close again in a short time.

C. Grounded motor circuit —

Cranking motors with a grounded armature or field coil can cause extensive damage to the series-parallelswitch. Circuits wired as indicated by Diagram A, would (5-19) have their batteries short-circuited through themotor if the motor were grounded. This condition would cause circuit breakers to open up and would badly burnthe charging contacts.

All series-parallel circuits would be endangered by the extremely high current flow caused by a groundedmotor when the series-parallel switch was in the cranking position. The large contact disc and wiring would bebadly burned by this situation.

D. Improper circuits —

Incorrect wiring circuitry, grounded or shorted circuits, accidental grounds or shorts caused by wrenchesor screw- drivers touching improper terminals of the switch or motor, are defects that can cause open fusesor blown circuit breakers. A thorough check of the wiring may be required in some of the above instances, tolocate the frayed or faulty insulation.


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OSCILLATING SOLENOIDS AND BURNED SOLENOID CONTACTS

Undercharged batteries can readily cause the above condition. When the starting switch of a solenoid-operated cranking motor circuit is closed the voltage available from the “A” and “B” batteries may be sufficientto close the solenoid contacts and energize the cranking motor. However, under the load of cranking, theundercharged battery voltage will rapidly drop to a point where the current flow through the “hold-in” coil of thesolenoid will not produce enough magnetic force to keep the solenoid closed against the solenoid and motorlever spring pressure.

The decrease in voltage, therefore, causes the solenoid contacts to open, breaking the high cranking cur-rent. Breaking this high-cranking current will cause considerable arcing that will burn the solenoid contacts andcontact disc. Once the solenoid is opened and if the starting switch remains energized, then sufficient magneticforce can be developed about the “hold-in” and “pull-in” coils of the solenoid to close the solenoid contacts.Thus, the above cycle of closing and opening occurs under conditions of operation with a low-charged batterysystem. This oscillating or clattering of the solenoid causes badly burned solenoid contacts and contact disc.

A fault within the solenoid itself (an open “hold-in” winding) can also be the cause of a clattering or oscillatingsolenoid. The state of charge of the battery will have no bearing on this type problem, since the open will causethe oscillating condition to occur, even though the batteries are fully charged.

Excessive resistance in series with either the solenoid or series-parallel switch control circuits (coil windings)can cause oscillation of the motor solenoid or series-parallel switch. Excessive resistance could be in the formof a loose connection, a corroded connection, or frayed and broken strands of wire.

As an example of how excessive resistance in series with the control circuit could af fect operation, let it beassumed that batteries low in state of charge are in use. The battery(s) available voltage may be sufficient toclose the solenoid contacts and series-parallel switch contacts and energize the cranking motor. However,under the load of cranking, the undercharged battery(s) voltage would drop. This drop in voltage, plus theresistance in series with the control circuit, would decrease the magnetism holding the plunger in position, andspring pressure could cause either the solenoid or series-parallel switch to open the cranking contact points.Opening of these points, while carrying heavy currents, would cause arcing and burning of the points.

Badly burned contact discs in the cranking motor solenoid or series-parallel switch causes excessive resis-tance in the cranking motor circuit. Even though an undercharged battery condition or excessive control circuitresistance is discovered and remedied, the cranking motor may not operate with sufficient voltage and currentto crank the engine. This may be due to badly burned points or high resistance, caused by the oscillatingsolenoid or series-parallel switch repeatedly making and breaking the cranking circuit.

BOTH “A” AND “B” BATTERIES UNDERCHARGED

In the event that all batteries, “A” and “B” are undercharged the problem is not necessarily in the series-parallelswitch, but may be elsewhere in the charging circuit, such as:

A. Low voltage regulator setting.B. Faulty generator.C. Possible faults in the wiring between the generator and the series-parallel switch or in the ground circuit

common to both batteries.D. A faulty regulator.E. Lack of sufficient charging time for batteries which can be caused by excessive low-speed driving,

stop-and-go driving, and periods of engine idling. All of these indicate a need for external charging or extra-output generator to keep the batteries up to satisfactory level of charge.


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“B” BATTERY UNDERCHARGED

It can be noted in the schematic wiring diagrams that the “A” battery takes advantage of the large crankingcables for its charging current. Battery “B”, however, has considerably more resistance in series with its charg-ing current in the form of more wiring, contact points and connections, as a result of its route through the series-parallel switch.

Experience has shown that many fuses and fuse holders can corrode when exposed to salt-spray conditions.This corrosion can introduce excessive resistance into the charging circuit of the “B” battery and it is for thisreason that fuses are no longer recommended.

Since there is more resistance in the charging current’s path to the “B” battery than to the “A” battery, itshould be expected that there would always be a slight difference in state of charge between the two batteries.Battery “A” will normally be higher in its charge level than will battery “B”.

Under normal operating conditions, it is possible to predict what a satisfactory difference in state-of-chargebetween battery “A” and “B” should be. This is dependent upon many variables within the batteries themselves,the wiring and condition of the circuit. For the best performance of the electrical system in which the series-parallel switch is used, it is recommended that the batteries in the “A” and “B” position be of the same capacity,size, number of plates, age and manufacture. This will assure that the batteries will have similar chargingcharacteristics and that when receiving approximately equal charging rates, the danger of overcharging onebattery and undercharging the other will be reduced.

It is further recommended that all batteries be adequately ventilated. Batteries located in confined areas willoverheat and become overcharged. Since the electrical loads on most vehicles are tapped off the “A” batteryand since there is a lower charging rate to the “B” battery, due to the increased resistance in its charging circuit,it is strongly recommended that periodically, the two batteries should be switched in position. This will lessonthe possibility of the “A” battery(s) becoming over- cycled with resultant positive plate shed which can cause alower battery capacity and a tendency to overcharge. This will also lessen the possibility of the “B” battery(s)becoming sulfated with the resultant tendency to remain in an undercharged condition.

If the “B” battery is chronologically undercharged, excessive resistance can be caused by:

1. Loose or corroded wiring connections at the series- parallel switch, or motor solenoid, the circuit breakeror fuse, ammeter, battery or ground.

2. Frayed or damaged wires.3. Oxidized or badly burned contact points or insufficient contact point pressure within the series-parallel

switch.

As an example of suspected excessive resistance, assume that the “A” battery of a vehicle checked at 1.270specific gravity, and the “B” battery checked at 1.230. The 40-point difference between the two batteries wouldindicate excessive resistance somewhere in the charging circuit to the “B” battery. The problem then becomesa matter of determining where the place or places of resistance exist in the circuit.

Resistances of the magnitude encountered in these circuits are extremely difficult to measure; however, theycan be easily detected by measuring the voltage drop in any portion of the circuit. To determine where theexcessive resistance exists, it will be necessary to have a good, broad scale voltmeter capable of reading tenthsof a volt and jumper lead of #4-gauge wire or larger, with heavy alligator clips soldered to either end of the lead.


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Using circuit “A” schematic wiring diagram as an example, proceed as follows to determine where excessiveresistance lies in the “B” battery charging circuit:

1. With engine not running, turn on headlights, disconnect one set of batteries (at this point, A and Bbatteries may not be identified). Note change in brightness of headlights. Reconnect batteries.

2. Repeat above step by disconnecting other set of batteries.3. A slight, reduced headlight brightness is normal when the “A” batteries are disconnected.4. If headlights dim or go out (Step 1 or 2 above), excessive resistance, or an open circuit is present in

“B” battery charging circuit. Condition of switch can determined by connecting a good jumper lead fromterminal #1 to #3 and #2 to #5 terminal. If headlights return to normal, a defective switch is indicated.

5. If no charge is noted in Step 4, remove jumpers and connect them across the two circuit breakers and notechange in brightness of headlights.

6. If no change is noted in Step 5, problem is in wiring or terminal connections.

More extensive testing can be done using a voltmeter and proceeding as follows:

1. Start vehicle engine and run at medium speed.2. Connect voltmeter across the “B” battery(s) and note the voltage indication.3. Connect jumper lead from #1 terminal of the series- parallel switch to the post furthest from ground of the

battery, and note voltmeter indication.4. If voltmeter reading has a marked increase after the jumper is applied, the bypassing of that portion of the

circuit indicates excessive resistance exists within this area. Note: No specific amount of voltage increasecan be suggested, since length and size of wire and battery state of charge will vary on many applications.The portions of the circuit that are bridged or bypassed by the jumper are:

a. The contact points between the #1 and #3 terminals of the series-parallel switch.b. The sections of wire between the #3 terminal of the series-parallel switch and the cranking

motor terminal, including the circuit breaker or fuse and ammeter.c. The ground wire from the cranking motor terminal to the battery post furthest from ground.

5. If voltmeter reading had a marked increase when the circuit was bypassed, as described in Step 4,then bridge or bypass each portion of the circuit described in Step 4 to determine which portion causes themost marked voltage increase indication on the voltmeter. It will be in this portion of the circuit that theexcessiveresistance exists. Cables should then be made into a good condition, terminals should be cleanand tight, or contacts should be cleaned to overcome the excessive resistance, in order that the chargelevel of the batteries can be maintained with satisfactory limits.

6. If the voltmeter indication is only slightly increased after performing Step 3, then that portion of the circuitcan be considered to be all right. The jumper lead should then be connected between the post of thebattery nearest the ground, and a good electrical ground on the vehicle. The voltmeter indication shouldthen be noted.

7. If the voltmeter reading has a marked increase, after jumper is applied, the bypassing of that portion of thecircuit indicates it is within this area that the excessive resistance exists. The portions of the circuit thatare bridged or bypassed are:

a. The wire between the battery post and the #2 terminal of the series-parallel switch.b. The contacts between the #2 terminal and #5 terminal of the series-parallel switch.c. The sections of wire between the #3 terminal of the series-parallel switch and the ground, including

the circuit breaker or fuse.


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BURNED OR MELTED CIRCUITS INSIDE SWITCH

Burned or melted circuits inside the series-parallel switch can be caused by: no circuit breakers being used,circuit breakers ratings too high, or improperly wired circuit breakers. Previous discussion has stressed theimportance of the circuit breakers and their function in the system.

Poor maintenance procedures can also cause melted or burned contacts inside the switch, particularly whenno circuit breaker protection is present. Examples of the procedures are:

1. Load testing of batteries on the vehicle without disconnecting them, so that individual batteries aretesting.

Since the “A” and “B” batteries are in parallel, load testing of one battery also draws current from theother through the series-parallel switch. The high currents involved can burn and melt the switch points.

Always disconnect batteries from the switch and other batteries before testing to prevent this occurrence.

2. Jump starting at 24 volts across the batteries with the series-parallel switch in the charging position.

If a 24 volt jump start source is placed across the vehicle battery(s) when the switch is in the chargingposition, then that source will charge the 12 volt battery(s) in parallel and the high currents will burn theswitch contacts.

When jump-starting, connect only 12 volt jump-start batteries across the 12 volt batteries of the vehicle.The jump-start batteries will then be placed in the series for 24 volts cranking at the proper time by theseries-parallel switch.

3. Accidental grounding of terminals with a wrench at the motor, solenoid, switch or battery terminals cancomplete high current circuits through the series-parallel switch contacts. Therefore, always disconnectthe ground connections of all batteries before working on electrical units.


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Series/Parallel Switch Wiring Diagrams

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Distributed by:

Toll Free: 1-800-325-2690Missouri: 636-629-1444 Fax: 1-800-973-6260

350 North Commercial, St. Clair, MO 63077Website: www.precisionrebuilders.com

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