light DODGE RAM 2001 Service Manual Online

in a completely discharged battery. At first, the
charging current (amperage) will be low. As the bat-
tery charges, the specific gravity of the electrolyte
will gradually rise.
The Battery Charging Time Table gives an indica-
tion of the time required to charge a typical battery
at room temperature based upon the battery state-of-
charge and the charger capacity.
BATTERY CHARGING TIME TABLE
Charging
Amperage5 Amps10
Amps20 Amps
Open Circuit
VoltageHours Charging @ 21É C
(70É F)
12.25 to 12.49 6 hours 3 hours 1.5
hours
12.00 to 12.24 10 hours 5 hours 2.5
hours
10.00 to 11.99 14 hours 7 hours 3.5
hours
Below 10.00 18 hours 9 hours 4.5
hours
STANDARD PROCEDURE - BUILT-IN
INDICATOR TEST
An indicator (hydrometer) built into the top of the
battery case provides visual information for battery
testing (Fig. 8). Like a hydrometer, the built-in indi-
cator measures the specific gravity of the battery
electrolyte. The specific gravity of the electrolyte
reveals the battery state-of-charge; however, it will
not reveal the cranking capacity of the battery. A load
test must be performed to determine the battery
cranking capacity. Refer to Standard Procedures for
the proper battery load test procedures.WARNING: IF THE BATTERY SHOWS SIGNS OF
FREEZING, LEAKING OR LOOSE POSTS, DO NOT
TEST, ASSIST-BOOST, OR CHARGE. THE BATTERY
MAY ARC INTERNALLY AND EXPLODE. PERSONAL
INJURY AND/OR VEHICLE DAMAGE MAY RESULT.
WARNING: EXPLOSIVE HYDROGEN GAS FORMS IN
AND AROUND THE BATTERY. DO NOT SMOKE,
USE FLAME, OR CREATE SPARKS NEAR THE BAT-
TERY. PERSONAL INJURY AND/OR VEHICLE DAM-
AGE MAY RESULT.
WARNING: THE BATTERY CONTAINS SULFURIC
ACID, WHICH IS POISONOUS AND CAUSTIC. AVOID
CONTACT WITH THE SKIN, EYES, OR CLOTHING.
IN THE EVENT OF CONTACT, FLUSH WITH WATER
AND CALL A PHYSICIAN IMMEDIATELY. KEEP OUT
OF THE REACH OF CHILDREN.
WARNING: IF THE BATTERY IS EQUIPPED WITH
REMOVABLE CELL CAPS, BE CERTAIN THAT EACH
OF THE CELL CAPS IS IN PLACE AND TIGHT
BEFORE THE BATTERY IS RETURNED TO SER-
VICE. PERSONAL INJURY AND/OR VEHICLE DAM-
AGE MAY RESULT FROM LOOSE OR MISSING
CELL CAPS.
Before testing, visually inspect the battery for any
damage (a cracked case or cover, loose posts, etc.)
that would cause the battery to be faulty. In order to
obtain correct indications from the built-in indicator,
it is important that the battery be level and have a
clean sight glass. Additional light may be required to
view the indicator.Do not use open flame as a
source of additional light.
To read the built-in indicator, look into the sight
glass and note the color of the indication (Fig. 9). The
battery condition that each color indicates is
described in the following list:
²Green- Indicates 75% to 100% battery state-of-
charge. The battery is adequately charged for further
testing or return to service. If the starter will not
crank for a minimum of fifteen seconds with a fully-
charged battery, the battery must be load tested.
Refer to Standard Procedures for the proper battery
load test procedures.
²Black or Dark- Indicates 0% to 75% battery
state-of-charge. The battery is inadequately charged
and must be charged until a green indication is visi-
ble in the sight glass (12.4 volts or more), before the
battery is tested further or returned to service. Refer
to Standard Procedures for the proper battery charg-
ing procedures. Also refer to Diagnosis and Testing
for more information on the possible causes of the
discharged battery condition.
Fig. 8 Built-In Indicator
1 - SIGHT GLASS
2 - BATTERY TOP
3 - GREEN BALL
4 - PLASTIC ROD
BR/BEBATTERY SYSTEM 8F - 11
BATTERY (Continued)

ENGINE STARTER MOTOR
DESCRIPTION
The starter motors used for the 5.9L diesel engine
and the 8.0L gasoline engine available in this model
are not interchangeable with each other, or with the
starter motors used for the other available engines.
The starter motors used for the 3.9L, 5.2L and the
5.9L gasoline engines available in this model are
interchangeable.
The starter motor for the 5.9L diesel engine is
mounted with three screws to the flywheel housing
on the left side of the engine. The starter motor for
the 8.0L gasoline engine is mounted with two screws
to the flange on the left rear corner of the engine
block, while the starter motors for all of the other
engines are mounted with one screw, a stud and a
nut to the manual transmission clutch housing or
automatic transmission torque converter housing and
are located on the left side of the engine.
Each of these starter motors incorporates several
of the same features to create a reliable, efficient,
compact, lightweight and powerful unit. The electric
motors of all of these starters have four brushes con-
tacting the motor commutator, and feature four elec-
tromagnetic field coils wound around four pole shoes.
The 3.9L, 5.2L, 5.9L and 8.0L gasoline engine starter
motors are rated at 1.4 kilowatts (about 1.9 horse-
power) output at 12 volts, while the 5.9L diesel
engine starter motor is rated at 2.7 kilowatts (about
3.6 horsepower) output at 12 volts.
All of these starter motors are serviced only as a
unit with their starter solenoids, and cannot be
repaired. If either component is faulty or damaged,
the entire starter motor and starter solenoid unit
must be replaced.
OPERATION
These starter motors are equipped with a gear
reduction (intermediate transmission) system. The
gear reduction system consists of a gear that is inte-
gral to the output end of the electric motor armature
shaft that is in continual engagement with a larger
gear that is splined to the input end of the starter
pinion gear shaft. This feature makes it possible to
reduce the dimensions of the starter. At the same
time, it allows higher armature rotational speed and
delivers increased torque through the starter pinion
gear to the starter ring gear.
The starter motors for all engines are activated by
an integral heavy duty starter solenoid switch
mounted to the overrunning clutch housing. This
electromechanical switch connects and disconnects
the feed of battery voltage to the starter motor, also
engaging and disengaging the starter pinion gear
with the starter ring gear.All starter motors use an overrunning clutch and
starter pinion gear unit to engage and drive a starter
ring gear that is integral to the flywheel (manual
transmission), torque converter or torque converter
drive plate (automatic transmission) mounted on the
rear crankshaft flange.
DIAGNOSIS AND TESTING - STARTER MOTOR
Correct starter motor operation can be confirmed
by performing the following free running bench test.
This test can only be performed with starter motor
removed from vehicle. Refer to Starter Specifications
for starter motor specifications.
(1) Remove starter motor from vehicle. Refer to
Starter MotorRemoval and Installation.
(2) Mount starter motor securely in a soft-jawed
bench vise. The vise jaws should be clamped on
mounting flange of starter motor. Never clamp on
starter motor by field frame.
(3) Connect suitable volt-ampere tester and 12-volt
battery to starter motor in series, and set ammeter to
100 ampere scale (250 ampere scale for diesel engine
starters). See instructions provided by manufacturer
of volt-ampere tester being used.
(4) Install jumper wire from solenoid terminal to
solenoid battery terminal. The starter motor should
operate. If starter motor fails to operate, replace
faulty starter motor assembly.
(5) Adjust carbon pile load of tester to obtain free
running test voltage. Refer to Specifications for the
starter motor free running test voltage specifications.
(6) Note reading on ammeter and compare this
reading to free running test maximum amperage
draw. Refer to Specifications for starter motor free
running test maximum amperage draw specifica-
tions.
(7) If ammeter reading exceeds maximum amper-
age draw specification, replace faulty starter motor
assembly.
STARTER MOTOR SOLENOID
This test can only be performed with starter motor
removed from vehicle.
(1) Remove starter motor. Refer toStarter Motor
Removal and Installation.
(2) Disconnect wire from solenoid field coil termi-
nal.
(3) Check for continuity between solenoid terminal
and solenoid field coil terminal with continuity tester
(Fig. 7). There should be continuity. If OK, go to Step
4. If not OK, replace faulty starter motor assembly.
(4) Check for continuity between solenoid terminal
and solenoid case (Fig. 8). There should be continuity.
If not OK, replace faulty starter motor assembly.
BR/BESTARTING 8F - 39

(3) Disconnect and isolate the battery negative
cable. Disconnect the 3-way instrument panel wire
harness connector for the heated mirror switch from
the heated mirror switch connector receptacle on the
back of the a/c heater control. Check for continuity
between the ground circuit cavity of the wire harness
connector and a good ground. There should be conti-
nuity. If OK, go to Step 4. If not OK, repair the open
ground circuit to ground as required.
(4) Reconnect the battery negative cable. Turn the
ignition switch to the On position. Check for battery
voltage at the fused ignition switch output (run/start)
circuit cavity of the 3-way instrument panel wire
harness connector for the heated mirror switch. If
OK, go to Step 5. If not OK, repair the open fused
ignition switch output (run/start) circuit to the fuse
in the JB as required.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Reconnect the 3-way instrument panel wire harness
connector for the heated mirror switch to the heated
mirror switch connector receptacle on the back of the
a/c heater control. Reconnect the battery negative
cable. Turn the ignition switch to the On position.
Depress and release the heated mirror switch. The
amber heated mirror system indicator lamp next to
the heated mirror switch button should light. If OK,
go to Step 6. If not OK, replace the faulty a/c heater
control.
(6) Back probe the fused heated mirror relay out-
put circuit cavity of the 3-way instrument panel wire
harness connector for the heated mirror switch on
the back of the a/c heater control and check for volt-
age (battery voltage less the resistance in both out-
side mirror heating grids). If OK, (Refer to 8 -
ELECTRICAL/HEATED MIRRORS/HEATED MIR-
ROR GRID - DIAGNOSIS AND TESTING).
HEATED MIRROR GRID
DESCRIPTION
Vehicles equipped with the optional heated mirror
system have an electrically operated heating grid
located behind the mirror glass of each power oper-
ated outside rear view mirror. The outside mirror
heating grid consists of two thin laminations of plas-
tic that approximate the outer dimensions and shape
of the mirror glass. A single length of resistor wire
weaves in a back and forth pattern between, and is
held in place by the two thin laminations of plastic.
The two ends of the resistor wire terminate near the
inboard edge of the grid, where they are soldered to
the ground feed and battery current feed wires con-
tained in the power mirror wire harness. The heating
grid is then sandwiched between the back of themolded plastic mirror glass case and the mirror
glass, where it remains in direct contact with the
back of the mirror glass at all times.
The outside mirror heating grids cannot be
repaired and, if faulty or damaged, the entire outside
power mirror unit must be replaced. Refer to Power
Mirrors for the service procedures.
OPERATION
One end of the outside mirror heating grid resistor
wire is connected to a ground feed at all times
through a body ground screw located inside the left
rear corner of the truck cab. Battery current is
directed to the other end of the outside mirror heat-
ing grid resistor wire by the energized heated mirror
relay when the heated mirror switch is in the On
position. As electrical current passes through the
heating grid, the resistance of the wire in the heating
grid converts some of that electrical current into
heat. The heat produced by the heating grid is then
conducted through the back of the mirror glass to
help keep the glass clear of ice, snow or fog.
DIAGNOSIS AND TESTING - HEATED MIRROR
GRID
For circuit descriptions and diagrams (Refer to
Appropriate Wiring Information).
(1) Disconnect and isolate the battery negative
cable. Disconnect the door wire harness connector
from the power mirror wire harness connector at the
power mirror with the inoperative heating grid.
Check for continuity between the ground circuit cav-
ity in the door wire harness connector for the power
mirror and a good ground. If OK, go to Step 2. If not
OK, repair the open ground circuit to ground as
required.
(2) Reconnect the battery negative cable. Turn the
ignition switch to the On position. Turn on the
heated mirror system. Check for voltage (battery
voltage less the resistance in the outside mirror heat-
ing grid that is still connected) at the fused heated
mirror relay output circuit cavity in the door wire
harness connector for the power mirror. If OK, go to
Step 3. If not OK, repair the open fused heated mir-
ror relay output circuit to the heater and air condi-
tioner control unit as required.
(3) Check the outside mirror heating grid by test-
ing for continuity between the ground circuit and the
fused heated mirror relay output circuit cavities in
the power mirror wire harness connector. There
should be continuity. If not OK, replace the faulty
power mirror. If OK, check the resistance through
the outside mirror heating grid. The correct resis-
tance should be from 10 to 16 ohms when measured
at an ambient temperature of 21É C (70É F). If not
OK, replace the faulty power mirror.
8G - 4 HEATED MIRRORSBR/BE
MIRROR SWITCH (Continued)

HEATED SEAT SYSTEM
TABLE OF CONTENTS
page page
HEATED SEAT SYSTEM
DESCRIPTION............................5
OPERATION.............................6
DIAGNOSIS AND TESTING..................6
HEATED SEAT SYSTEM..................6
DRIVER SEAT HEATER SWITCH
DESCRIPTION............................7
OPERATION.............................7
DIAGNOSIS AND TESTING..................8
HEATED SEAT SWITCH...................8
REMOVAL...............................9
INSTALLATION............................9
HEATED SEAT ELEMENT
DESCRIPTION...........................10
OPERATION.............................10
DIAGNOSIS AND TESTING.................11HEATED SEAT ELEMENT & SENSOR.......11
HEATED SEAT RELAY
DESCRIPTION...........................11
OPERATION.............................12
DIAGNOSIS AND TESTING.................12
HEATED SEAT RELAY...................12
REMOVAL..............................13
INSTALLATION...........................13
PASSENGER SEAT HEATER SWITCH
DESCRIPTION...........................13
OPERATION.............................14
DIAGNOSIS AND TESTING.................14
HEATED SEAT SWITCH..................14
REMOVAL..............................15
INSTALLATION...........................16
HEATED SEAT SYSTEM
DESCRIPTION
Individually controlled electrically heated front
seats are available factory-installed optional equip-
ment on the Ram quad cab models that are also
equipped with the optional SLT Plus (leather) trimpackage. Vehicles with this option can be visually
identified by the two separate heated seat switches
mounted in a bezel located in the lower right corner
of the instrument cluster bezel, next to the radio
receiver (Fig. 1). The heated seat system allows the
front seat driver and passenger to select from two
different levels of supplemental electrical seat heat-
ing, or no seat heating to suit their individual com-
fort requirements. The heated seat system for this
vehicle includes the following major components:
²The heated seat switches, including two heated
seat Light-Emitting Diode (LED) indicator lamps and
an incandescent back lighting bulb for each switch.
²The heated seat module, also referred to as the
Seat Heat Interface Module (SHIM), which contains
the solid state electronic control and diagnostic logic
circuitry for the heated seat system. Refer to the
Electronic Control Modules section of the service
manual for heated seat module information.
²The heated seat elements and sensors, which
are integral to the individual front seat cushion and
front seat back trim covers.
²The heated seat relay, which controls the avail-
ability of battery current to the heated seat module
or SHIM.
Following are general descriptions of the major
components in the heated seat system. See the own-
er's manual in the vehicle glove box for more infor-
mation on the features, use and operation of the
heated seat system. Refer toPower Seatin the
index of this service manual for the location of com-
plete heated seat system wiring diagrams.
Fig. 1 Heated Seat System Switches
1 - RADIO RECEIVER
2 - HEATED SEAT SWITCHES
BR/BEHEATED SEAT SYSTEM 8G - 5

OPERATION
The heated seat module receives fused battery cur-
rent through the energized heated seat relay in the
Junction Block (JB) only when the engine is running.
The heated seat switches receive battery current
through a fused ignition switch output (run) circuit
only when the ignition switch is in the On position.
The heated seat module shares a common ground cir-
cuit with each of the heated seat elements. The
heated seat elements will only operate when the sur-
face temperature of the seat cushion cover at the
heated seat sensors is below the designed tempera-
ture set points of the system.
The heated seat module will automatically turn off
the heated seat elements if it detects a short in the
heated seat element circuit or a heated seat sensor
value that is out of range. The heated seat system
will also be turned off automatically whenever the
ignition switch is turned to any position except On or
if the engine quits running. If the ignition switch is
turned to the Off position or if the engine quits run-
ning while a heated seat is turned ON, the heated
seat will remain Off after the engine is restarted
until a heated seat switch is depressed again.
The heated seat module monitors inputs from the
heated seat sensors and the heated seat switches. In
response to these inputs the heated seat module uses
its internal programming to control outputs to the
heated seat elements in both front seats and to con-
trol the heated seat LED indicator lamps located in
both of the heated seat switches. The heated seat
module is also programmed to provide a self-diagnos-
tic capability. When the module detects certain fail-
ures within the heated seat system, it will provide a
visual indication of the failure by flashing the indica-
tor lamps in the heated seat switches.
DIAGNOSIS & TESTING - HEATED SEAT
SYSTEM
SELF-DIAGNOSIS
The heated seat system is capable of performing
some self-diagnostics. The following table depicts the
various failure modes which will be reported to the
vehicle operator or technician by flashing the individ-
ual heated seat switch Light Emitting Diode (LED)
indicator lamps. See the Heated Seat System Self-Di-
agnosis table for the diagnostic routines. The driver
side heated seat switch indicator lamps will flash if a
failure occurs in the driver side heated seat, and the
passenger side heated seat switch indicator lamps
will flash for a passenger side heated seat failure. If
a monitored heated seat system failure occurs, the
switch indicator lamps will flash at a pulse rate of
about one-half second on, followed by about one-half
second off for a duration of about one minute afterthe switch for the faulty heated seat is depressed in
either the Low or High direction. This process will
repeat every time the faulty heated seat switch is
actuated until the problem has been corrected.
Heated Seat System Self-Diagnosis
Monitored FailureSwitch High
Indicator LampSwitch Low
Indicator Lamp
Heated Seat
Element ShortedFlashing Flashing
Heated Seat
Element OpenFlashing Off
Heated Seat
Sensor Value Out
of RangeOff Flashing
TESTING
Refer toPower Seatin the index of this service
manual for the location of complete heated seat sys-
tem wiring diagrams. Before testing the individual
components in the heated seat system, perform the
following preliminary checks:
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
²If the heated seat switch back lighting and the
cluster illumination lamps do not illuminate with the
headlamps or park lamps turned On, refer toInstru-
ment Clusterin the index of this service manual for
the location of the proper cluster illumination lamps
diagnosis and testing procedures. If the heated seat
switch back lighting does not illuminate, but the
cluster illumination lamps do illuminate with the
headlamps or park lamps turned On, refer to
Heated Seat Switchin this section for the location
of the proper heated seat switch diagnosis and test-
ing procedure.
²If a single indicator lamp for one heated seat
switch does not operate and the heated seat elements
do heat, refer toHeated Seat Switchin this section
for the location of the proper heated seat switch diag-
nosis and testing procedure.
8G - 6 HEATED SEAT SYSTEMBR/BE
HEATED SEAT SYSTEM (Continued)

²If both indicator lamps for a heated seat switch
operate, but the heated seat elements do not heat,
refer toHeated Seat Modulein Electronic Control
Modules for the location of the proper heated seat
module diagnosis and testing procedures. Also refer
to the Body Diagnostic Manual for additional diagno-
sis and testing procedures.
²If none of the indicator lamps for both heated
seat switches will operate and the heated seat ele-
ments for both seats do not heat, refer toHeated
Seat Relayin this section for the location of the
proper heated seat relay diagnosis and testing proce-
dures.
²If the an indicator lamp on either heated seat
switch remains illuminated after the heated seat has
been turned Off, refer toHeated Seat Modulein
Electronic Control Modules for the location of the
proper heated seat module diagnosis and testing pro-
cedures. Also refer to the Body Diagnostic Manual for
additional diagnosis and testing procedures.
DRIVER SEAT HEATER
SWITCH
DESCRIPTION
The heated seat switches used on vehicles with
this option are both mounted in a heated seat switch
bezel (Fig. 2), which replaces the standard equipmentcubby bin located in the lower right corner of the
instrument cluster bezel next to the radio receiver.
The two switches are snapped into the mounting
holes of the heated seat switch bezel, and the heated
seat switch bezel is secured with three screws to the
instrument panel. The mounts for the heated seat
switch bezel are concealed behind the instrument
cluster bezel. The two heated seat switches are iden-
tical in appearance and construction, except for the
location of a keyway in the single connector recepta-
cle on the back of each switch. The instrument panel
wire harness connectors for the heated seat switches
are keyed to match the connector receptacles on the
switches so that the two heated seat switches can
only be connected to the proper heated seat.
The momentary, bidirectional rocker-type heated
seat switch provides a resistor-multiplexed signal to
the heated seat module. Each switch has a center
neutral position and momentary Low and High posi-
tions so that both the driver and the front seat pas-
senger can select a preferred seat heating mode.
Each heated seat switch has two Light-Emitting
Diode (LED) indicator lamps, which indicate the
selected mode (Low or High) of the seat heater for
each seat and to provide diagnostic feedback for the
heated seat system. Each switch also has an incan-
descent bulb, which provides panel lamps dimmer
controlled back lighting of the switch nomenclature
when the headlamps or park lamps are turned on.
The two LED indicator lamps and the incandescent
bulb in each heated seat switch cannot be repaired. If
the indicator lamps or back lighting bulb are faulty
or damaged, the individual heated seat switch unit
must be replaced.
OPERATION
The heated seat switches receive battery current
through a fused ignition switch output (run) circuit
when the ignition switch is in the On position.
Depressing the heated seat switch rocker to its
momentary High or Low position provides a hard-
wired resistor multiplexed voltage request signal to
the heated seat module to power the heated seat ele-
ment of the selected seat and maintain the requested
temperature setting. If the heated seat switch is
depressed to a different position (Low or High) than
the currently selected state, the heated seat module
will change states to support the new selection. If a
heated seat switch is depressed a second time to the
same position as the currently selected state, the
heated seat module interprets the second input as a
request to turn the seat heater off. The heated seat
module will then turn the heated seat elements for
that seat off.
Fig. 2 Heated Seat Switches
1 - DRIVER SIDE SWITCH
2 - PASSENGER SIDE SWITCH
3 - INDICATOR LAMPS
4 - HEATED SEAT SWITCH BEZEL
BR/BEHEATED SEAT SYSTEM 8G - 7
HEATED SEAT SYSTEM (Continued)

The indicator lamps in the heated seat switches
receive battery current through a fused ignition
switch output (run) circuit when the ignition switch
is in the On position. The ground side of each indi-
cator lamp is controlled by a separate (high or low/
driver or passenger) indicator lamp driver circuit by
the heated seat module. The heated seat module con-
trol of the switch indicator lamps also allows the
module to provide diagnostic feedback to the vehicle
operator to indicate monitored heated seat system
faults by flashing the indicator lamps on and off. One
side of the incandescent back lighting bulb in each
heated seat switch is connected to ground at all
times. The other side of the incandescent bulb is con-
nected to the fused panel lamps dimmer switch sig-
nal circuit. These bulbs are energized when the park
lamps or headlamps are turned on, and their illumi-
nation intensity is controlled by the panel lamps dim-
mer switch.
DIAGNOSIS & TESTING - HEATED SEAT
SWITCH
Refer toWiring Diagramsfor the location of com-
plete heated seat system wiring diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) If the problem being diagnosed involves inoper-
ative heated seat switch back lighting and the cluster
illumination lamps operate, go to Step 2. If the prob-
lem being diagnosed involves inoperative heated seat
switch back lighting and the cluster illumination
lamps are also inoperative, refer toInstrument
Clusterin the index of this service manual for the
proper cluster illumination lamps diagnosis and test-
ing procedures. If the problem being diagnosed
involves inoperative heated seat switch indicator
lamps and the heated seat elements do not heat,
refer to Step 4. If the problem being diagnosed
involves inoperative heated seat switch indicator
lamps and the heated seat elements do heat, go to
Step 8. If the problem being diagnosed involves a
heated seat switch indicator lamp that remains illu-minated after the heated seat has been turned Off,
refer toHeated Seat Modulein Electronic Control
Modules for the location of the proper heated seat
module diagnosis and testing procedures. Also refer
to the Body Diagnostic Manual for additional diagno-
sis and testing procedures.
(2) Disconnect and isolate the battery negative
cable. Remove the heated seat switch and bezel unit
from the instrument panel. Disconnect the instru-
ment panel wire harness connector from the connec-
tor receptacle on the back of the heated seat switch
to be tested. Check for continuity between the ground
circuit cavity of the instrument panel wire harness
connector for the heated seat switch and a good
ground. There should be continuity. If OK, go to Step
3. If not OK, repair the open ground circuit to ground
as required.
(3) Reconnect the battery negative cable. Turn the
park lamps on with the headlamp switch. Rotate the
panel lamps dimmer thumbwheel on the headlamp
switch upward to just before the interior lamps
detent. Check for battery voltage at the fused panel
lamps dimmer switch signal circuit cavity of the
instrument panel wire harness connector for the
heated seat switch. If OK, replace the faulty heated
seat switch. If not OK, repair the open fused panel
lamps dimmer switch signal circuit to the fuse in the
Junction Block (JB) as required.
(4) Check the fused ignition switch output (run)
fuse in the Junction Block (JB). If OK, go to Step 5.
If not OK, repair the shorted circuit or component as
required and replace the faulty fuse.
(5) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run) fuse in the JB. If OK, go to Step 6. If
not OK, repair the open fused ignition switch output
(run) circuit to the ignition switch as required.
(6) Disconnect and isolate the battery negative
cable. Remove the heated seat switch and bezel unit
from the instrument panel. Disconnect the instru-
ment panel wire harness connector from the connec-
tor receptacle on the back of the heated seat switch
to be tested. Reconnect the battery negative cable.
Turn the ignition switch to the On position. Check
for battery voltage at the fused ignition switch out-
put (run) circuit cavity of the instrument panel wire
harness connector for the heated seat switch. If OK,
go to Step 7. If not OK, repair the open fused ignition
switch output (run) circuit to the JB fuse as required.
(7) Check the continuity and resistance values of
the heated seat switch in the Neutral, Low and High
positions as shown in the Heated Seat Switch Conti-
nuity chart (Fig. 3). If OK, refer toHeated Seat
Modulein Electronic Control Modules for the loca-
tion of the proper heated seat module diagnosis and
testing procedures. Also refer to the Body Diagnostic
8G - 8 HEATED SEAT SYSTEMBR/BE
DRIVER SEAT HEATER SWITCH (Continued)

The momentary, bidirectional rocker-type heated
seat switch provides a resistor-multiplexed signal to
the heated seat module. Each switch has a center
neutral position and momentary Low and High posi-
tions so that both the driver and the front seat pas-
senger can select a preferred seat heating mode.
Each heated seat switch has two Light-Emitting
Diode (LED) indicator lamps, which indicate the
selected mode (Low or High) of the seat heater for
each seat and to provide diagnostic feedback for the
heated seat system. Each switch also has an incan-
descent bulb, which provides panel lamps dimmer
controlled back lighting of the switch nomenclature
when the headlamps or park lamps are turned on.
The two LED indicator lamps and the incandescent
bulb in each heated seat switch cannot be repaired. If
the indicator lamps or back lighting bulb are faulty
or damaged, the individual heated seat switch unit
must be replaced.
OPERATION
The heated seat switches receive battery current
through a fused ignition switch output (run) circuit
when the ignition switch is in the On position.
Depressing the heated seat switch rocker to its
momentary High or Low position provides a hard-
wired resistor multiplexed voltage request signal to
the heated seat module to power the heated seat ele-
ment of the selected seat and maintain the requestedtemperature setting. If the heated seat switch is
depressed to a different position (Low or High) than
the currently selected state, the heated seat module
will change states to support the new selection. If a
heated seat switch is depressed a second time to the
same position as the currently selected state, the
heated seat module interprets the second input as a
request to turn the seat heater off. The heated seat
module will then turn the heated seat elements for
that seat off.
The indicator lamps in the heated seat switches
receive battery current through a fused ignition
switch output (run) circuit when the ignition switch
is in the On position. The ground side of each indi-
cator lamp is controlled by a separate (high or low/
driver or passenger) indicator lamp driver circuit by
the heated seat module. The heated seat module con-
trol of the switch indicator lamps also allows the
module to provide diagnostic feedback to the vehicle
operator to indicate monitored heated seat system
faults by flashing the indicator lamps on and off. One
side of the incandescent back lighting bulb in each
heated seat switch is connected to ground at all
times. The other side of the incandescent bulb is con-
nected to the fused panel lamps dimmer switch sig-
nal circuit. These bulbs are energized when the park
lamps or headlamps are turned on, and their illumi-
nation intensity is controlled by the panel lamps dim-
mer switch.
DIAGNOSIS & TESTING - HEATED SEAT
SWITCH
Refer toWiring Diagramsfor the location of com-
plete heated seat system wiring diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE AIRBAG SYSTEM BEFORE
ATTEMPTING ANY STEERING WHEEL, STEERING
COLUMN, OR INSTRUMENT PANEL COMPONENT
DIAGNOSIS OR SERVICE. DISCONNECT AND ISO-
LATE THE BATTERY NEGATIVE (GROUND) CABLE,
THEN WAIT TWO MINUTES FOR THE AIRBAG SYS-
TEM CAPACITOR TO DISCHARGE BEFORE PER-
FORMING FURTHER DIAGNOSIS OR SERVICE. THIS
IS THE ONLY SURE WAY TO DISABLE THE AIRBAG
SYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) If the problem being diagnosed involves inoper-
ative heated seat switch back lighting and the cluster
illumination lamps operate, go to Step 2. If the prob-
lem being diagnosed involves inoperative heated seat
switch back lighting and the cluster illumination
lamps are also inoperative, refer toInstrument
Fig. 9 Heated Seat Switches
1 - DRIVER SIDE SWITCH
2 - PASSENGER SIDE SWITCH
3 - INDICATOR LAMPS
4 - HEATED SEAT SWITCH BEZEL
8G - 14 HEATED SEAT SYSTEMBR/BE
PASSENGER SEAT HEATER SWITCH (Continued)

(3) The relay normally open terminal (87) is con-
nected to the common feed terminal (30) in the ener-
gized position. This terminal supplies battery voltage
to the horn(s). There should be continuity between
the cavity for relay terminal 87 and the horn relay
output circuit cavity of each horn wire harness con-
nector at all times. If OK, go to Step 4. If not OK,
repair the open circuit to the horn(s) as required.
(4) The coil battery terminal (86) is connected to
the electromagnet in the relay. It is connected to bat-
tery voltage and should be hot at all times. Check for
battery voltage at the cavity for relay terminal 86. If
OK, go to Step 5. If not OK, repair the open circuit to
the fuse in the PDC as required.
(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded
through the horn switch when the horn switch is
depressed. On vehicles equipped with the Vehicle
Theft Security System (VTSS), the horn relay coil
ground terminal can also be grounded by the Central
Timer Module (CTM) in response to certain inputs
related to the VTSS or Remote Keyless Entry (RKE)
system. Check for continuity to ground at the cavity
for relay terminal 85. There should be continuity
with the horn switch depressed, and no continuity
with the horn switch released. If not OK, (Refer to 8
- ELECTRICAL/HORN/HORN SWITCH - DIAGNO-
SIS AND TESTING).
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the cover from the Power Distribution
Center (PDC) (Fig. 3) .(3) See the fuse and relay layout label affixed to
the underside of the PDC cover for horn relay iden-
tification and location.
(4) Remove the horn relay from the PDC.
INSTALLATION
(1) See the fuse and relay layout label affixed to
the underside of the PDC cover for the proper horn
relay location.
(2) Position the horn relay in the proper receptacle
in the PDC.
(3) Align the horn relay terminals with the termi-
nal cavities in the PDC receptacle.
(4) Push down firmly on the horn relay until the
terminals are fully seated in the terminal cavities in
the PDC receptacle.
(5) Install the cover onto the PDC.
(6) Reconnect the battery negative cable.
HORN SWITCH
DESCRIPTION
A center-blow, normally open, resistive membrane-
type horn switch is secured with heat stakes to the
back side of the driver side airbag module trim cover
in the center of the steering wheel (Fig. 4) . The
switch consists of two plastic membranes, one that is
flat and one that is slightly convex. These two mem-
branes are secured to each other around the perime-
ter. Inside the switch, the centers of the facing
surfaces of these membranes each has a grid made
with an electrically conductive material applied to it.
One of the grids is connected to a circuit that pro-
vides it with continuity to ground at all times. The
grid of the other membrane is connected to the horn
relay control circuit.
Fig. 2 Horn Relay
TERMINAL LEGEND
NUMBER IDENTIFICATION
30 COMMON FEED
85 COIL GROUND
86 COIL BATTERY
87 NORMALLY OPEN
87A NORMALLY CLOSED
Fig. 3 Power Distribution Center
1 - COVER
2 - POWER DISTRIBUTION CENTER
8H - 4 HORNBR/BE
HORN RELAY (Continued)

(7) If the dimension is approximately 2.018 inches,
the cam gear will have to be rotated.
(8) Attach a socket to the vibration damper mount-
ing bolt and rotate engine until the 1.818 inch
dimension is attained.
(9) Install the sensor into the timing case/cover
with a slight rocking action until the paper spacer
contacts the camshaft gear. Do not install the sensor
mounting bolt. Do not twist the sensor into position
as damage to the o-ring or tearing of the paper
spacer may result.
(10) Scratch a scribe line into the timing chain
case/cover to indicate depth of sensor (Fig. 14).
(11) Remove the sensor from timing chain case/
cover.
(12) Remove the paper spacer from the sensor.
This step must be followed to prevent the paper
spacer from getting into the engine lubrication sys-
tem.
(13) Again, apply a small amount of engine oil to
sensor o-ring.
(14) Again, install the sensor into the timing case/
cover with a slight rocking action until the sensor is
aligned to scribe line.(15) Install sensor mounting bolt and tighten to 6
N´m (50 in. lbs.) torque.
(16) Connect engine wiring harness to sensor.
Replacing With a New Sensor
(1) Apply a small amount of engine oil to the sen-
sor o-ring (Fig. 14).
A low and high area are machined into the cam-
shaft drive gear (Fig. 15). The sensor is positioned in
the timing gear cover so that a small air gap (Fig.
15) exists between the face of sensor and the high
machined area of cam gear.
Before the sensor is installed, the cam gear may
have to be rotated. This is to allow the high
machined area on the gear to be directly in front of
the sensor mounting hole opening on the timing gear
cover.
Do not install sensor with gear positioned at
low area (Fig. 16) or (Fig. 15). When the engine
is started, the sensor will be broken.
(2) Using a 1/2 in. wide metal ruler, measure the
distance from the cam gear to the face of the sensor
mounting hole opening on the timing gear cover (Fig.
16).
(3) If the dimension is approximately 1.818 inches,
it is OK to install sensor. Proceed to step Step 9.
(4) If the dimension is approximately 2.018 inches,
the cam gear will have to be rotated.
(5) Attach a socket to the vibration damper mount-
ing bolt and rotate engine until the 1.818 inch
dimension is attained.
(6) Install the sensor into the timing case/cover
with a slight rocking action. Do not twist the sensor
into position as damage to the o-ring may result.
Push the sensor all the way into the cover until the
rib material on the sensor (Fig. 13) contacts the cam-
shaft gear.
(7) Install the mounting bolt and tighten to 6 N´m
(50 in. lbs.) torque.
(8) Connect sensor wiring harness to engine har-
ness.
When the engine is started, the rib material will be
sheared off the face of sensor. This will automatically
set sensor air gap.
DISTRIBUTOR
DESCRIPTION
All 3.9L/5.2L/5.9L engines are equipped with a
camshaft driven mechanical distributor (Fig. 17) con-
taining a shaft driven distributor rotor. All distribu-
tors are equipped with an internal camshaft position
(fuel sync) sensor (Fig. 17).
Fig. 16 Sensor Depth Dimensions
1 - 2.01888DO NOT INSTALL SENSOR
2 - SENSOR MOUNTING HOLE OPENING
3 - SENSOR CENTER LINE
4 - TIMING CHAIN COVER
5 - 1.81888OK TO INSTALL SENSOR
6 - CAM DRIVE GEAR
7 - HIGH MACHINED AREA
8 - LOW MACHINED AREA
8I - 10 IGNITION CONTROLBR/BE
CAMSHAFT POSITION SENSOR (Continued)