DODGE RAM 2002 Service Repair Manual

(4) Disconnect the starter motor signal wire har-
ness connector, located on the PDC housing.
(5) Disengage wire harness assembly pushpin
retainers.
(6) From under the vehicle, disengage wire har-
ness assembly pushpin retainers.
(7) Remove the positive battery cable from the
starter motor B+ terminal stud.
(8) Remove the starter motor trigger wire from the
starter motor.
(9) Remove the positive cable wire harness assem-
bly from the vehicle.
NEGATIVE CABLE REMOVAL - GASOLINE
ENGINE
Both the battery negative cable and the battery
positive cable are serviced in the battery wire har-
ness. If either battery cable is damaged or faulty, the
battery wire harness unit must be replaced.
(1) Turn the ignition switch to the Off position. Be
certain that all electrical accessories are turned off.
(2) Loosen the battery negative cable terminal
clamp pinch-bolt hex nut.
(3) Disconnect the battery negative cable terminal
clamp from the battery negative terminal post. If
necessary, use a battery terminal puller to remove
the terminal clamp from the battery post.
(4) Remove the negative cable jumper from the left
side of the radiator closure panel.
(5) Remove the negative cable jumper from the left
side of the frame assembly.
(6) Remove the PDC cover and remove the gener-
ator output wire from the PDC.
(7) Following the wire, remove the pushpin retain-
ers holding the wire assembly in place.
(8) Remove the negative cable eyelet from the
power steering pump pivot bolt.
(9) Remove the generator output wire from the
generator.
(10) Remove the negative battery cable assembly,
by fishing out from under the compressor mounting
bracket, if equipped.
INSTALLATION
POSITIVE CABLE INSTALLATION - GASOLINE
ENGINE
(1) Position the battery wire harness into the
engine compartment.
(2) Install the positive battery cable on the battery.
(3) Install the positive battery cable on the PDC.
(4) Install the cover on the PDC.
(5) Connect the starter motor signal wire harness
connector, located on the PDC housing.(6) Install wire harness assembly pushpin retain-
ers in their original position.
(7) From under the vehicle, install wire harness
assembly pushpin retainers.
(8) Install and tighten the nut that secures the
battery positive cable eyelet terminal to the B(+) ter-
minal stud on the starter solenoid. Tighten the nut to
10 N´m (90 in. lbs.).
(9) Connect the starter motor trigger wire on the
starter motor.
(10) Reconnect the battery positive cable terminal
clamp to the battery positive terminal post. Tighten
the terminal clamp pinch-bolt hex nut to 4 N´m (35
in. lbs.).
(11) Apply a thin coating of petroleum jelly or
chassis grease to the exposed surfaces of the battery
cable terminal clamps and the battery terminal
posts.
NEGATIVE CABLE INSTALLATION - GASOLINE
ENGINE
(1) Position the battery wire harness into the
engine compartment and under the compressor
mounting bracket, if equipped.
(2) Install and tighten the nut that secures the
battery negative cable ground eyelet terminal to the
stud on the power steering pump pivot bolt.
(3) Install the generator output cable eyelet termi-
nal onto the generator output terminal stud.
(4) Install and tighten the nut that secures the
generator output cable eyelet terminal to the genera-
tor output terminal stud. Tighten the nut to 8.4 N´m
(75 in. lbs.).
(5) Position the cover for the generator output ter-
minal stud housing onto the back of the generator
and snap it into place.
(6) Secure wire assembly in place with pushpin
retainers in there original positions.
(7) Install and tighten the screw that secures the
battery negative cable eyelet terminal to the radiator
closure panel, near the battery. Tighten the screw to
40 in. lbs.
(8) Install and tighten the screw that secures the
battery negative cable eyelet terminal to the left
front side of the frame assembly. Tighten the screw
to 80 in. lbs.
(9) Install and tighten the nut that secures the
battery positive cable eyelet terminal and the gener-
ator output cable eyelet terminal to the PDC B(+)
terminal stud. Tighten the nut to 80 in. lbs.
(10) Reconnect the battery negative cable terminal
clamp to the battery negative terminal post. Tighten
the terminal clamp pinch-bolt hex nut to 35 in. lbs.
(11)
Apply a thin coating of petroleum jelly or chas-
sis grease to the exposed surfaces of the battery cable
terminal clamps and the battery terminal posts.
8F - 22 BATTERY SYSTEMBR/BE
BATTERY CABLE (Continued)

BATTERY TRAY
DESCRIPTION
The battery is mounted in a molded plastic tray
(Fig. 25) with an integral support located in the left
front corner of the engine compartment. A U-nut held
in a molded formation on each side of the battery
tray provides anchor points for the battery hold down
bolts. The battery tray is secured on the outboard
side to the inner fender shield by two hex screws
with washers, and from underneath the integral bat-
tery tray support is secured to the left front wheel-
house inner panel by two stud plates. Each stud
plate has two studs and is secured by two nuts with
washers. The stud plate that secures the front of the
battery tray support to the wheelhouse inner panel is
installed through the wheelhouse panel from the top.
The stud plate that secures the rear of the battery
tray support to the wheelhouse inner panel is
installed through the wheelhouse panel from the bot-
tom.
A hole in the bottom of the battery tray is fitted
with a battery temperature sensor (Refer to 8 -
ELECTRICAL/CHARGING/BATTERY TEMPERA-
TURE SENSOR - DESCRIPTION). Models that are
equipped with an optional vehicle speed control sys-tem have the speed control servo secured to the inte-
gral battery tray support.
Models that are equipped with the diesel engine
option have a second battery tray located in the right
front corner of the engine compartment. This second
battery tray and its mounting are mirror image of
the standard equipment left battery tray. However,
the right battery tray and support have no provisions
for a battery temperature sensor or a speed control
servo mounting bracket.
OPERATION
The battery tray provides a secure mounting loca-
tion and supports the battery. On some vehicles, the
battery tray also provides the anchor point/s for the
battery holddown hardware. The battery tray and
the battery holddown hardware combine to secure
and stabilize the battery in the engine compartment,
which prevents battery movement during vehicle
operation. Unrestrained battery movement during
vehicle operation could result in damage to the vehi-
cle, the battery, or both.
REMOVAL
(1) Remove the battery from the battery tray
(Refer to 8 - ELECTRICAL/BATTERY SYSTEM/BAT-
TERY - REMOVAL).
(2) If the left battery tray is being removed,
remove the battery temperature sensor from the left
battery tray (Refer to 8 - ELECTRICAL/CHARGING/
BATTERY TEMPERATURE SENSOR - REMOVAL).
(3) Remove the two screws with washers that
secure the outboard side of the battery tray to the
inner fender shield (Fig. 26).
(4) From the engine compartment, remove the two
nuts with washers that secure the rear of the battery
tray support to the two studs that extend through
the top of the front wheelhouse inner panel.
(5) From inside the front fender wheelhouse,
remove the two nuts with washers that secure the
front of the battery tray support to the two studs
that extend through the underside of the front wheel-
house inner panel.
(6) From inside the front fender wheelhouse,
remove the stud plate that secures the rear of the
battery tray support from the underside of the front
wheelhouse inner panel.
(7) From the engine compartment, remove the bat-
tery tray and the stud plate that secures the front of
the battery tray support from the front wheelhouse
inner panel as a unit.
(8) If the vehicle is equipped with the optional
vehicle speed control package, the speed control servo
must be removed from the left battery tray support
to complete battery tray removal.
Fig. 25 Battery Tray - Typical
1 - STUD PLATE (2)
2 - NUT AND WASHER (4)
3 - FRONT WHEELHOUSE INNER PANEL
4 - SPEED CONTROL SERVO
5 - TRAY
6 - SCREW AND WASHER (2)
7 - BATTERY TREMPERATURE SENSOR
8 - U-NUT (2)
9 - FENDER INNER SHIELD
BR/BEBATTERY SYSTEM 8F - 23

INSTALLATION
(1) Clean and inspect the battery tray (Refer to 8 -
ELECTRICAL/BATTERY SYSTEM - CLEANING).
(2) If the vehicle is equipped with the optional
vehicle speed control package, the speed control servo
must be installed onto the left battery tray support
to complete battery tray installation.(3) Install the stud plate onto the front of the bat-
tery tray support.
(4) From the engine compartment, position the
battery tray and the stud plate that secures the front
of the battery tray support onto the front wheelhouse
inner panel as a unit.
(5) From inside the front fender wheelhouse,
loosely install the two nuts with washers that secure
the front of the battery tray support to the two studs
that extend through the underside of the front wheel-
house inner panel.
(6) From inside the front fender wheelhouse, posi-
tion the stud plate that secures the rear of the bat-
tery tray support onto the underside of the front
wheelhouse inner panel.
(7) From the engine compartment, loosely install
the two nuts with washers that secure the rear of the
battery tray support to the two studs that extend
through the top of the front wheelhouse inner panel.
(8) Install and tighten the two screws with wash-
ers that secure the outboard side of the battery tray
to the inner fender shield. Tighten the screws to 15.8
N´m (140 in. lbs.).
(9) Final tighten the four nuts with washers that
secure the battery tray support to the stud plates on
the front wheelhouse inner panel. Tighten the nuts
to 15.8 N´m (140 in. lbs.).
(10) If the left battery tray is being installed,
install the battery temperature sensor onto the left
battery tray (Refer to 8 - ELECTRICAL/CHARGING/
BATTERY TEMPERATURE SENSOR - INSTALLA-
TION).
(11) Install the battery onto the battery tray (Refer
to 8 - ELECTRICAL/BATTERY SYSTEM/BATTERY -
INSTALLATION).
Fig. 26 Left Battery Tray Remove/Install - Typical for
Right Battery Tray
1 - STUD PLATE (2)
2 - NUT AND WASHER (4)
3 - FRONT WHEELHOUSE INNER PANEL
4 - SPEED CONTROL SERVO
5 - TRAY
6 - SCREW AND WASHER (2)
7 - BATTERY TREMPERATURE SENSOR
8 - U-NUT (2)
9 - FENDER INNER SHIELD
8F - 24 BATTERY SYSTEMBR/BE
BATTERY TRAY (Continued)

CHARGING
TABLE OF CONTENTS
page page
CHARGING
DESCRIPTION.........................25
OPERATION...........................25
DIAGNOSIS AND TESTING - CHARGING
SYSTEM............................25
SPECIFICATIONS
GENERATOR RATINGS.................26
SPECIFICATIONS - TORQUE -
GENERATOR/CHARGING SYSTEM........27
BATTERY TEMPERATURE SENSOR
DESCRIPTION.........................27OPERATION...........................27
REMOVAL.............................27
INSTALLATION.........................28
GENERATOR
DESCRIPTION.........................28
OPERATION...........................28
REMOVAL.............................28
INSTALLATION.........................30
VOLTAGE REGULATOR
DESCRIPTION.........................30
OPERATION...........................30
CHARGING
DESCRIPTION
The charging system consists of:
²Generator
²Electronic Voltage Regulator (EVR) circuitry
within the Powertrain Control Module (PCM)
²Ignition switch
²Battery (refer to 8, Battery for information)
²Battery temperature sensor
²Check Gauges Lamp (if equipped)
²Voltmeter (refer to 8, Instrument Panel and
Gauges for information)
²Wiring harness and connections (refer to 8, Wir-
ing Diagrams for information)
OPERATION
The charging system is turned on and off with the
ignition switch. The system is on when the engine is
running and the ASD relay is energized. When the
ASD relay is on, voltage is supplied to the ASD relay
sense circuit at the PCM. This voltage is connected
through the PCM and supplied to one of the genera-
tor field terminals (Gen. Source +) at the back of the
generator.
The amount of direct current produced by the gen-
erator is controlled by the EVR (field control) cir-
cuitry contained within the PCM. This circuitry is
connected in series with the second rotor field termi-
nal and ground.
A battery temperature sensor, located in the bat-
tery tray housing, is used to sense battery tempera-
ture. This temperature data, along with data from
monitored line voltage, is used by the PCM to vary
the battery charging rate. This is done by cycling theground path to control the strength of the rotor mag-
netic field. The PCM then compensates and regulates
generator current output accordingly.
All vehicles are equipped with On-Board Diagnos-
tics (OBD). All OBD-sensed systems, including EVR
(field control) circuitry, are monitored by the PCM.
Each monitored circuit is assigned a Diagnostic Trou-
ble Code (DTC). The PCM will store a DTC in elec-
tronic memory for certain failures it detects. Refer to
On-Board Diagnostics in 25, Emission Control Sys-
tem for more DTC information and a list of codes.
The Check Gauges Lamp (if equipped) monitors:
charging system voltage,engine coolant tempera-
ture and engine oil pressure. If an extreme condition
is indicated, the lamp will be illuminated. This is
done as reminder to check the three gauges. The sig-
nal to activate the lamp is sent via the CCD bus cir-
cuits. The lamp is located on the instrument panel.
Refer to 8, Instrument Panel and Gauges for addi-
tional information.
DIAGNOSIS AND TESTING - CHARGING
SYSTEM
The following procedures may be used to diagnose
the charging system if:
²the check gauges lamp (if equipped) is illumi-
nated with the engine running
²the voltmeter (if equipped) does not register
properly
²an undercharged or overcharged battery condi-
tion occurs.
Remember that an undercharged battery is often
caused by:
²accessories being left on with the engine not
running
BR/BECHARGING 8F - 25

²a faulty or improperly adjusted switch that
allows a lamp to stay on. Refer to Ignition-Off Draw
Test in 8, Battery for more information.
INSPECTION
The Powertrain Control Module (PCM) monitors
critical input and output circuits of the charging sys-
tem, making sure they are operational. A Diagnostic
Trouble Code (DTC) is assigned to each input and
output circuit monitored by the On-Board Diagnostic
(OBD) system. Some charging system circuits are
checked continuously, and some are checked only
under certain conditions.
Refer to Diagnostic Trouble Codes in; Powertrain
Control Module; Electronic Control Modules for more
DTC information. This will include a complete list of
DTC's including DTC's for the charging system.
To perform a complete test of the charging system,
refer to the appropriate Powertrain Diagnostic Proce-
dures service manual and the DRBtscan tool. Per-
form the following inspections before attaching the
scan tool.
(1) Inspect the battery condition. Refer to 8, Bat-
tery for procedures.(2) Inspect condition of battery cable terminals,
battery posts, connections at engine block, starter
solenoid and relay. They should be clean and tight.
Repair as required.
(3) Inspect all fuses in both the fuseblock and
Power Distribution Center (PDC) for tightness in
receptacles. They should be properly installed and
tight. Repair or replace as required.
(4) Inspect generator mounting bolts for tightness.
Replace or tighten bolts if required. Refer to the Gen-
erator Removal/Installation section of this group for
torque specifications.
(5) Inspect generator drive belt condition and ten-
sion. Tighten or replace belt as required. Refer to
Belt Tension Specifications in 7, Cooling System.
(6) Inspect automatic belt tensioner (if equipped).
Refer to 7, Cooling System for information.
(7) Inspect generator electrical connections at gen-
erator field, battery output, and ground terminal (if
equipped). Also check generator ground wire connec-
tion at engine (if equipped). They should all be clean
and tight. Repair as required.
SPECIFICATIONS
GENERATOR RATINGS
TYPE PART NUMBER RATED SAE AMPS ENGINESMINIMUM TEST
AMPS
DENSO 56028920AB 1365.9L
GAS100
DENSO 56029913AA 1175.9L
GAS90
BOSCH 56028237AB 1175.9L
GAS90
BOSCH 56028238AB 1365.9L
GAS100
DENSO 56027221AD 1365.9L
DIESEL120
BOSCH 56028239AB 1365.9L
DIESEL120
BOSCH 56028560AA 136 8.0L 100
DENSO 560289200AC 136 8.0L 100
8F - 26 CHARGINGBR/BE
CHARGING (Continued)

SPECIFICATIONS - TORQUE - GENERATOR/
CHARGING SYSTEM
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Generator Mounting Bolts
- Gas Engine41 30-
Generator Upper Mounting
Bolt - Diesel Engine54 40 -
Generator Pivot Bolt/Nut -
Diesel Engine54 40 -
Generator Mounting
Bracket-to-Engine Bolt -
Diesel Engine24 18 -
Generator B+ Cable
Eyelet Nut12 9 108
BATTERY TEMPERATURE
SENSOR
DESCRIPTION
The Battery Temperature Sensor (BTS) is attached
to the battery tray located under the battery.
OPERATION
The BTS is used to determine the battery temper-
ature and control battery charging rate. This temper-
ature data, along with data from monitored line
voltage, is used by the PCM to vary the battery
charging rate. System voltage will be higher at colder
temperatures and is gradually reduced at warmer
temperatures.
The PCM sends 5 volts to the sensor and is
grounded through the sensor return line. As temper-
ature increases, resistance in the sensor decreases
and the detection voltage at the PCM increases.
The BTS is also used for OBD II diagnostics. Cer-
tain faults and OBD II monitors are either enabled
or disabled, depending upon BTS input (for example,
disable purge and enable Leak Detection Pump
(LDP) and O2 sensor heater tests). Most OBD II
monitors are disabled below 20ÉF.
REMOVAL
The battery temperature sensor is located under
the vehicle battery (Fig. 1) and is attached (snapped
into) a mounting hole on battery tray. On models
equipped with a diesel engine (dual batteries), only
one sensor is used. The sensor is located under the
battery on drivers side of vehicle.
(1) Remove battery. Refer to 8, Battery for proce-
dures.Fig. 1 Battery Temperature Sensor Location
1 - BATT. TEMP. SENSOR
2 - BATTERY HOLD DOWN STRAP
3 - PIGTAIL HARNESS
4 - U-NUT
5 - U-NUT
6 - ELEC. CONNEC.
BR/BECHARGING 8F - 27
CHARGING (Continued)

(2) Disconnect sensor pigtail harness from engine
wire harness.
(3) Pry sensor straight up from battery tray
mounting hole.
INSTALLATION
The battery temperature sensor is located under
the vehicle battery (Fig. 1) and is attached (snapped
into) a mounting hole on battery tray. On models
equipped with a diesel engine (dual batteries), only
one sensor is used. The sensor is located under the
battery on drivers side of vehicle.
(1) Feed pigtail harness through mounting hole in
top of battery tray and press sensor into top of tray
(snaps in).
(2) Connect pigtail harness.
(3) Install battery. Refer to 8A, Battery for proce-
dures.
GENERATOR
DESCRIPTION
The generator is belt-driven by the engine using a
serpentine type drive belt. It is serviced only as a
complete assembly. If the generator fails for any rea-
son, the entire assembly must be replaced.
OPERATION
As the energized rotor begins to rotate within the
generator, the spinning magnetic field induces a cur-
rent into the windings of the stator coil. Once the
generator begins producing sufficient current, it also
provides the current needed to energize the rotor.
The Y type stator winding connections deliver the
induced alternating current to 3 positive and 3 neg-
ative diodes for rectification. From the diodes, recti-
fied direct current is delivered to the vehicle
electrical system through the generator battery ter-
minal.
Although the generators appear the same exter-
nally, different generators with different output rat-
ings are used on this vehicle. Be certain that the
replacement generator has the same output rating
and part number as the original unit. Refer to Gen-
erator Ratings in the Specifications section at the
back of this group for amperage ratings and part
numbers.
Noise emitting from the generator may be caused
by: worn, loose or defective bearings; a loose or defec-
tive drive pulley; incorrect, worn, damaged or misad-
justed fan drive belt; loose mounting bolts; a
misaligned drive pulley or a defective stator or diode.
REMOVAL
WARNING: DISCONNECT NEGATIVE CABLE FROM
BATTERY BEFORE REMOVING BATTERY OUTPUT
WIRE (B+ WIRE) FROM GENERATOR. FAILURE TO
DO SO CAN RESULT IN INJURY OR DAMAGE TO
ELECTRICAL SYSTEM.
(1) Disconnect negative battery cable at battery.
Diesel Engines: Disconnect both negative battery
cables at both batteries.
(2) Remove generator drive belt. Refer to 7, Cool-
ing System for procedure.
(3) Gasoline Engines: Remove generator pivot and
mounting bolts/nut (Fig. 2) or (Fig. 3).
(4) Diesel Engines: Loosen (but do not remove)
generator mounting bracket-to-engine bolt (Fig. 4).
(5) All Engines: Remove upper generator mounting
bolt and lower mounting bolt/nut.
(6) Remove B+ terminal mounting nut at rear of
generator (Fig. 5) or (Fig. 6). Disconnect terminal
from generator.
(7) Disconnect field wire connector at rear of gen-
erator by pushing on connector tab.
(8) Remove generator from vehicle.
Fig. 2 Remove/Install GeneratorÐ5.9L Engines
1 - MOUNTING BOLT
2 - GENERATOR
3 - MOUNTING BRACKET
4 - MOUNTING BOLT/NUT
8F - 28 CHARGINGBR/BE
BATTERY TEMPERATURE SENSOR (Continued)

Fig. 3 Remove/Install GeneratorÐ8.0L Engine
1 - MOUNTING BOLT
2 - GENERATOR
3 - NUT
4 - MOUNTING BRACKET
5 - MOUNTING BOLT
Fig. 4 Remove/Install GeneratorÐDiesel Engine
1 - UPPER MOUNTING BOLT
2 - BRACKET-TO-ENGINE BOLT
3 - LOWER MOUNTING BOLT/NUT
4 - GENERATOR
Fig. 5 Generator ConnectorsÐTypical Bosch
1 - FIELD WIRE CONNECTOR
2 - FIELD WIRES
3 - B+ (OUTPUT TERMINAL)
Fig. 6 Generator ConnectorsÐTypical Denso
1 - FIELD WIRES
2 - B+ (OUTPUT TERMINAL)
3 - FIELD WIRE CONNECTOR
BR/BECHARGING 8F - 29
GENERATOR (Continued)

INSTALLATION
(1) Position generator to engine and snap field
wire connector into rear of generator.
(2) Install B+ terminal eyelet to generator stud.
Tighten mounting nut to 12 N´m (108 in. lbs.) torque.
(3) Install generator mounting fasteners and
tighten as follows:
²Generator mounting boltÐAll gas powered
enginesÐ41 N´m (30 ft. lbs.) torque.
²Generator pivot bolt/nutÐAll gas powered
enginesÐ41 N´m (30 ft. lbs.) torque.
²Generator mounting boltÐDiesel powered
enginesÐ54 N´m (40 ft. lbs.) torque.
²Generator pivot bolt/nutÐDiesel powered
enginesÐ54 N´m (40 ft. lbs.) torque.
CAUTION: Never force a belt over a pulley rim
using a screwdriver. The synthetic fiber of the belt
can be damaged.
CAUTION: When installing a serpentine accessory
drive belt, the belt MUST be routed correctly. The
water pump will be rotating in the wrong direction if
the belt is installed incorrectly, causing the engine
to overheat. Refer to belt routing label in engine
compartment, or refer to Belt Schematics in Group
7, Cooling System.
(4) Install generator drive belt. Refer to 7, Cooling
System for procedure.
(5) Install negative battery cable(s) to battery(s).
VOLTAGE REGULATOR
DESCRIPTION
The Electronic Voltage Regulator (EVR) is not a
separate component. It is actually a voltage regulat-
ing circuit located within the Powertrain Control
Module (PCM). The EVR is not serviced separately. If
replacement is necessary, the PCM must be replaced.
OPERATION
The amount of direct current produced by the gen-
erator is controlled by EVR circuitry contained
within the PCM. This circuitry is connected in series
with the generators second rotor field terminal and
its ground.
Voltage is regulated by cycling the ground path to
control the strength of the rotor magnetic field. The
EVR circuitry monitors system line voltage (B+) and
battery temperature (refer to Battery Temperature
Sensor for more information). It then determines a
target charging voltage. If sensed battery voltage is
0.5 volts or lower than the target voltage, the PCM
grounds the field winding until sensed battery volt-
age is 0.5 volts above target voltage. A circuit in the
PCM cycles the ground side of the generator field up
to 100 times per second (100Hz), but has the capabil-
ity to ground the field control wire 100% of the time
(full field) to achieve the target voltage. If the charg-
ing rate cannot be monitored (limp-in), a duty cycle
of 25% is used by the PCM in order to have some
generator output. Also refer to Charging System
Operation for additional information.
8F - 30 CHARGINGBR/BE
GENERATOR (Continued)

STARTING
TABLE OF CONTENTS
page page
STARTING
DESCRIPTION.........................31
OPERATION...........................31
DIAGNOSIS AND TESTING - STARTING
SYSTEM............................32
SPECIFICATIONS
STARTING SYSTEM...................36
SPECIFICATIONS - TORQUE - STARTING
SYSTEM............................37
STARTER MOTOR
DESCRIPTION.........................37OPERATION...........................37
DIAGNOSIS AND TESTING - STARTER
MOTOR .............................38
REMOVAL.............................38
INSTALLATION.........................40
STARTER MOTOR RELAY
DESCRIPTION.........................41
OPERATION...........................41
DIAGNOSIS AND TESTING - STARTER RELAY . 41
REMOVAL.............................42
INSTALLATION.........................42
STARTING
DESCRIPTION
The starting system consists of:
²Starter relay
²Starter motor (including an integral starter sole-
noid)
Other components to be considered as part of start-
ing system are:
²Battery
²Battery cables
²Ignition switch and key lock cylinder
²Clutch pedal position switch (manual transmis-
sion)
²Park/neutral position switch (automatic trans-
mission)
²Wire harnesses and connections.
The Battery, Starting, and Charging systems oper-
ate in conjunction with one another, and must be
tested as a complete system. For correct operation of
starting/charging systems, all components used in
these 3 systems must perform within specifications.
When attempting to diagnose any of these systems, it
is important that you keep their interdependency in
mind.
The diagnostic procedures used in each of these
groups include the most basic conventional diagnostic
methods, to the more sophisticated On-Board Diag-
nostics (OBD) built into the Powertrain Control Mod-
ule (PCM). Use of an induction-type milliampere
ammeter, volt/ohmmeter, battery charger, carbon pile
rheostat (load tester), and 12-volt test lamp may be
required.
Certain starting system components are monitored
by the PCM and may produce a Diagnostic Trouble
Code (DTC). Refer to Emission Control. See Diagnos-tic Trouble Codes for additional information and a
list of codes.OPERATION
The starting system components form two separate
circuits. A high-amperage feed circuit that feeds the
starter motor between 150 and 350 amperes (700
amperes - diesel engine), and a low-amperage control
circuit that operates on less than 20 amperes. The
high-amperage feed circuit components include the
battery, the battery cables, the contact disc portion of
the starter solenoid, and the starter motor. The low-
amperage control circuit components include the igni-
tion switch, the clutch pedal position switch (manual
transmission), the park/neutral position switch (auto-
matic transmission), the starter relay, the electro-
magnetic windings of the starter solenoid, and the
connecting wire harness components.
If the vehicle is equipped with a manual transmis-
sion, it has a clutch pedal position switch installed in
series between the ignition switch and the coil bat-
tery terminal of the starter relay. This normally open
switch prevents the starter relay from being ener-
gized when the ignition switch is turned to the
momentary Start position, unless the clutch pedal is
depressed. This feature prevents starter motor oper-
ation while the clutch disc and the flywheel are
engaged. The starter relay coil ground terminal is
always grounded on vehicles with a manual trans-
mission.
If the vehicle is equipped with an automatic trans-
mission, battery voltage is supplied through the low-
amperage control circuit to the coil battery terminal
of the starter relay when the ignition switch is
turned to the momentary Start position. The park/
neutral position switch is installed in series between
the starter relay coil ground terminal and ground.
BR/BESTARTING 8F - 31