service CHRYSLER CARAVAN 2003 Service Manual

ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION) section for more DTC information.
The Check Gauges Lamp (if equipped) or Battery
Lamp monitors:charging system voltage,engine
coolant temperature and engine oil pressure. If an
extreme condition is indicated, the lamp will be illu-
minated. The signal to activate the lamp is sent via
the PCI bus circuits. The lamp is located on the
instrument panel. Refer to the Instrument Cluster
section for additional information.
(If equipped with inlet air temperature sensor) The
PCM uses the inlet air temperature sensor to control
the charge system voltage. This temperature, along
with data from monitored line voltage, is used by the
PCM to vary the battery charging rate. The system
voltage is higher at cold temperatures and is gradu-
ally reduced as the calculated battery temperature
increases.
The ambient temperature sensor is used to control
the battery voltage based upon ambient temperature
(approximation of battery temperature). The PCM
maintains the optimal output of the generator by
monitoring battery voltage and controlling it to a
range of 13.5 - 14.7 volts based on battery tempera-
ture. The system target voltage is 13.5 ± 14.7 volts.
However the actual voltage go below this during
heavy electrical loads and generator speeds. Also the
actual voltage can be lower than the target voltage
between the battery and the battery voltage sense
circuit, approximately 0.2 Ð 0.3 volts.
DIAGNOSIS AND TESTING - ON-BOARD
DIAGNOSTIC SYSTEM
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 OBD system. Some
circuits are checked continuously and some are
checked only under certain conditions.
If the OBD system senses that a monitored circuit
is bad, it will put a DTC into electronic memory. The
DTC will stay in electronic memory as long as the
circuit continues to be bad. The PCM is programmed
to clear the memory after 40 good trip if the problem
does not occur again.
DIAGNOSTIC TROUBLE CODES
A DTC description can be read using the DRBIIIt
scan tool. Refer to the appropriate Powertrain Diag-
nostic Procedures manual for information.
A DTC does not identify which component in a cir-
cuit is bad. Thus, a DTC should be treated as a
symptom, not as the cause for the problem. In some
cases, because of the design of the diagnostic test
procedure, a DTC can be the reason for another DTCto be set. Therefore, it is important that the test pro-
cedures be followed in sequence, to understand what
caused a DTC to be set.
ERASING DIAGNOSTIC TROUBLE CODES
The DRBIIItScan Tool must be used to erase a
DTC.
The following procedures may be used to diagnose
the charging system if:
²the check gauges lamp or battery lamp 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
²a faulty or improperly adjusted switch that
allows a lamp to stay on. Refer to Ignition-Off Draw
Test (Refer to 8 - ELECTRICAL/BATTERY SYSTEM/
BATTERY - STANDARD PROCEDURE)
²loose generator belt.
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 DRBIIItscan tool.
Perform the following inspections before attaching
the scan tool.
(1) Inspect the battery condition. Refer to the Bat-
tery section (Refer to 8 - ELECTRICAL/BATTERY
SYSTEM - DIAGNOSIS AND TESTING) for proce-
dures.
(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) or IPM (if
equipped) for tightness in receptacles. They should be
properly installed and tight. Repair or replace as
required.
RSCHARGING8F-21
CHARGING (Continued)
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SPECIAL TOOLS
BATTERY TEMPERATURE
SENSOR
DESCRIPTION
(NGC Vehicles) The PCM incorporates a Battery
Temperature Sensor (BTS) on its circuit board.
OPERATION
The PCM uses the temperature of the battery area
to control the charge system voltage. This tempera-
ture, along with data from monitored line voltage, is
used by the PCM to vary the battery charging rate.
The system voltage is higher at cold temperatures
and is gradually reduced as temperature around the
battery increases.
(NGC Vehicles) The ambient temperature sensor is
used to control the battery voltage based upon ambi-
ent temperature (approximation of battery tempera-
ture). The PCM maintains the optimal output of the
generator by monitoring battery voltage and control-
ling it to a range of 13.5 - 14.7 volts based on battery
temperature. The system target voltage is 13.5 ± 14.7
volts. However the actual voltage go below this dur-
ing heavy electrical loads and generator speeds. Also
the actual voltage can be lower than the target volt-
age between the battery and the battery voltage
sense circuit, approximately 0.2 Ð 0.3 volts.
The battery temperature sensor is also used for
OBD II diagnostics. Certain faults and OBD II mon-
itors are either enabled or disabled depending upon
the battery temperature sensor input (example: dis-
able purge and EGR, enable LDP). Most OBD II
monitors are disabled below 20ÉF.
REMOVAL
The battery temperature sensor is not serviced sep-
arately. If replacement is necessary, the PCM must
be replaced.
GENERATOR
DESCRIPTION
The generator is belt-driven by the engine. The
generator produces DC voltage at the B+ terminal. If
the generator is failed, the generator assembly sub-
components (generator and decoupler pulley) must be
inspected for individual failure and replaced accord-
ingly.
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 AC current to 3 positive and 3 negative
diodes for rectification. From the diodes, rectified DC
current is delivered to the vehicles electrical system
through the generator, battery, and ground terminals.
Excessive or abnormal noise emitting from the gen-
erator may be caused by:
²Worn, loose or defective bearings
²Loose or defective drive pulley (2.4L) or decou-
pler (3.3/3.8L)
²Incorrect, worn, damaged or misadjusted drive
belt
²Loose mounting bolts
²Misaligned drive pulley
²Defective stator or diode
²Damaged internal fins
REMOVAL
REMOVAL - 2.4L
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Disconnect the Inlet Air Temperature sensor.
(4) Remove the Air Box, refer to the Engine/Air
Cleaner for more information.
(5) Remove the EVAP Purge solenoid from its
bracket and reposition.
(6) Disconnect the push-in field wire connector
from back of generator.
(7) Remove nut holding B+ wire terminal to back
of generator.
(8) Separate B+ terminal from generator.
(9) Remove accessory drive belt, refer to the Cool-
ing System section for proper procedures.
(10) Remove the generator.
GENERATOR DECOUPLER 8433
RSCHARGING8F-23
CHARGING (Continued)
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GENERATOR DECOUPLER
PULLEY
DESCRIPTION
The Generator Decoupler is a one way clutch (Fig.
3). It is attached to the generator and replaces the
standard pulley. It is a non-serviceable item and is to
be replaced as an assembly. It is a dry operation (no
grease or lubricants). The operation of it is not tem-
perature sensitive and has a low sensitivity to elec-
trical load.
OPERATION
The generator decoupler is a one way clutch and
should be replaced as an assembly. It is designed to
help reduce belt tension fluctuation, reduce fatigue
loads, improve belt life, reduce hubloads on compo-
nents, and reduce noise.
DIAGNOSIS AND TESTING - GENERATOR DECOUPLER PULLEY
CONDITION VERIFICATION PROCEDURE POSSIBLE CAUSES CORRECTION
Does not drive
generator (Generator
not Charging)1. Start engine and allow
engine to idle.Clutch failure Replace Decoupler
2.Verify generator pulley is
rotating.
3. View generator internal fins
thru generator housing.
4. Fins either do not rotate or
rotate very erratic.
5. Rotate decoupler pulley in
clockwise direction then
quickly rotate in
counterclockwise direction to
see if clutch engages.
Noise from generator
at engine shut down.1. Start engine and allow
engine to idle.Defective decoupler
pulley bearing.Replace decoupler pulley.
2. Shutdown engine and listen
to generator.
3. Noise heard just as engine
stops. Sounds like a click.
4. Remove accessory drive
belt.
5. Verify rotation in
counterclock wise direction is
rough.
Fig. 3 GENERATOR DECOUPLER 3.3/3.8L
RSCHARGING8F-25
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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 DC current produced by the gener-
ator 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 on
SBEC vehicles or the power side on the NGC vehi-
cles, to control the strength of the rotor magnetic
field. The EVR circuitry monitors system line voltage
at the PDC and calculated battery temperature or
inlet air temperature sensor (refer to Inlet Air Tem-
perature Sensor, if equipped, for more information ).
It then determines a target charging voltage. If
sensed battery voltage is lower than the target volt-
age, the PCM feeds the field winding until sensed
battery voltage is at the target voltage. A circuit in
the PCM cycles the feed side of the generator field at
250 times per second (250Hz), but has the capability
to feed the field control wire 100% of the time (full
field) to achieve the target voltage. If the charging
rate cannot be monitored (limp-in), a duty cycle of
20% is used by the PCM in order to have some gen-
erator output. Also refer to Charging System Opera-
tion for additional information.
Fig. 7 DECOUPLER INSTALLATION (Litens)
RSCHARGING8F-27
GENERATOR DECOUPLER PULLEY (Continued)
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STARTING
TABLE OF CONTENTS
page page
STARTING
DESCRIPTION.........................28
OPERATION...........................28
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - STARTING
SYSTEM TEST.......................28
DIAGNOSIS AND TESTING - CONTROL
CIRCUIT TEST........................30
DIAGNOSIS AND TESTING - FEED CIRCUIT
RESISTANCE TEST....................32
DIAGNOSIS AND TESTING - FEED CIRCUIT
TEST...............................33SPECIFICATIONS
Torques.............................33
STARTER ...........................34
STARTER MOTOR
REMOVAL
REMOVAL - 2.4L......................34
REMOVAL - 3.3/3.8L...................35
INSTALLATION
INSTALLATION - 2.4L..................35
INSTALLATION - 3.3/3.8L................36
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.
OPERATION
These components form two separate circuits. A
high amperage circuit that feeds the starter motor up
to 300+ amps, and a control circuit that operates on
less than 20 amps.
The PCM controls a double start over-ride safety
that does not allow the starter to be engaged if the
engine is already running.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - STARTING
SYSTEM TEST
For circuit descriptions and diagrams, refer to the
Wiring Diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO THE PASSIVE RESTRAINT SYS-
TEMS BEFORE ATTEMPTING STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. FAILURE
TO TAKE THE PROPER PRECAUTIONS COULD
RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
INSPECTION
Before removing any unit from the starting system
for repair or diagnosis, perform the following inspec-
tions:
²Battery- Visually inspect the battery for indi-
cations of physical damage and loose or corroded
cable connections. Determine the state-of-charge and
cranking capacity of the battery. Charge or replace
8F - 28 STARTINGRS
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CONDITION POSSIBLE CAUSE CORRECTION
2. STARTING CIRCUIT
WIRING FAULTY.2. REFER TO THE FEED CIRCUIT RESISTANCE TEST AND
THE FEED CIRCUIT TEST IN THIS SECTION. REPAIR AS
NECESSARY.
3. STARTER ASSEMBLY
FAULTY.3. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
4. ENGINE SEIZED. 4. REFER TO THE ENGINE SECTION, FOR DIAGNOSTIC AND
SERVICE PROCEDURES.
5. LOOSE
CONNECTION AT
BATTERY, PDC,
STARTER, OR ENGINE
GROUND.5. INSPECT FOR LOOSE CONNECTIONS.
6. FAULTY TEETH ON
RING GEAR.6. ROTATE FLYWHEEL 360É, AND INSPECT TEETH AND RING
GEAR REPLACED IF DAMAGED.
STARTER
ENGAGES,
SPINS OUT
BEFORE
ENGINE
STARTS.1. BROKEN TEETH ON
STARTER RING GEAR.1. REMOVE STARTER. INSPECT RING GEAR AND REPLACE
IF NECESSARY.
2. STARTER ASSEMBLY
FAULTY.2. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
STARTER DOES
NOT
DISENGAGE.1. STARTER
IMPROPERLY
INSTALLED.1. INSTALL STARTER. TIGHTEN STARTER MOUNTING
HARDWARE TO CORRECT TORQUE SPECIFICATIONS.
2. STARTER RELAY
FAULTY.2. REFER TO RELAY TEST, IN THIS SECTION. REPLACE
RELAY, IF NECESSARY.
3. IGNITION SWITCH
FAULTY.3. REFER TO IGNITION SWITCH TEST, IN THE STEERING
SECTION. REPLACE SWITCH, IF NECESSARY.
4. STARTER ASSEMBLY
FAULTY.4. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
5. FAULTY TEETH ON
RING GEAR.5. ROTATE FLYWHEEL 360É, AND INSPECT TEETH AND RING
GEAR REPLACED IF DAMAGED.
DIAGNOSIS AND TESTING - CONTROL
CIRCUIT TEST
The starter control circuit has:
²Starter motor with integral solenoid
²Starter relay
²Transmission range sensor, or Park/Neutral
Position switch with automatic transmissions
²Ignition switch
²Battery
²All related wiring and connections
²Powertrain Control Module (PCM)
CAUTION: Before performing any starter tests, the
ignition and fuel systems must be disabled.²To disable ignition and fuel systems, disconnect
the Automatic Shutdown Relay (ASD). The ASD relay
is located in the Power Distribution Center (PDC).
Refer to the PDC cover for the proper relay location.
STARTER SOLENOID
WARNING: CHECK TO ENSURE THAT THE TRANS-
MISSION IS IN THE PARK POSITION WITH THE
PARKING BRAKE APPLIED.
(1) Verify battery condition. Battery must be in
good condition with a full charge before performing
any starter tests. Refer to Battery Tests.
(2) Perform Starter Solenoid test BEFORE per-
forming the starter relay test.
8F - 30 STARTINGRS
STARTING (Continued)
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WINDSHIELD GRID
DIAGNOSIS AND TESTING - SYSTEM TEST
Electrically heated rear window defogger or the
heated windshield wiper deicer operation can be
checked on the vehicle in the following manner:
(1) Turn the ignition switch to the ON position.
(2) Using a ammeter on the battery, turn the rear
defogger control switch to the ON position, a distinct
increase in amperage draw should be noted.
(3) The rear window defogger or the heated wind-
shield wiper deicer operation can be checked by feel-
ing the glass. A distinct difference in temperature
between the grid lines and adjacent clear glass can
be detected in 3 to 4 minutes of operation.
(4) Using a DC voltmeter (Fig. 4) contact terminal
B with the negative lead, and terminal A with the
positive lead. The voltmeter should read 10-14 volts.
(5) Indicator light illumination means that there is
power available at the switch only and does not nec-
essarily verify system operation.
(6) If turning the defogger switch ON, no distinct
current draw on the ammeter the problem should be
isolated in the following manner:
²Confirm that ignition switch is ON.
²Ensure that the heated rear window or the
heated windshield wiper deicer feed pigtail is con-
nected to the wiring harness and that the ground
pigtail is in fact grounded.
²Ensure that the proper fuse in the PDC is OK.
(7) When the above steps have been completed and
the system is still inoperative it may be necessary to
connect a DRBIII scan tool and refer to the Diagnos-
tic Service Manual, you may also check for the fol-
lowing being defective:
²HVAC control assembly
²Rear window defogger relay in the PDC portion
of the IPM.
²Rear window defogger relay control circuity in
the FCM portion of the IPM.
²Check for loose connector or a wire pushed out
of connector.
²Rear window or the windshield grid lines (all
grid lines would have to be broken, or one of the feed
pigtails not connected to the bus bar, for no ammeter
deflection).
(8) If turning the switch ON produces severe volt-
meter deflection, the circuit should be closely checked
for a shorting condition.
(9) If the system operation has been verified but
indicator LED does not light, replace the HVAC con-
trol assembly.
(10) For detailed wiring information, refer to the
appropriate section for Wiring Diagrams.
STANDARD PROCEDURE - GRID LINE AND
TERMINAL REPAIR
WARNING: REPAIR KIT MAY CAUSE SKIN OR EYE
IRRITATION. CONTAINS EPOXY RESIN AND AMINE
TYPE HARDENER, HARMFUL IF SWALLOWED.
AVOID CONTACT WITH SKIN AND EYES. FOR SKIN,
WASH AFFECTED AREAS WITH SOAP AND WATER.
DO NOT TAKE INTERNALLY. IF TAKEN INTER-
NALLY, INDUCE VOMITING; CALL A PHYSICIAN
IMMEDIATELY. IF IN CONTACT WITH EYES, FLUSH
WITH PLENTY OF WATER. USE WITH ADEQUATE
VENTILATION. DO NOT USE NEAR FIRE OR FLAME.
CONTENTS CONTAINS 3% FLAMMABLE SOL-
VENTS. KEEP OUT OF REACH OF CHILDREN.
The repair for the front windshield or the rear win-
dow grids are the same.
The repair of grid lines and replacement of the ter-
minal is possible using the MopartRepair Package
or equivalent.
(1) Clean area surrounding grid line or terminal
by gently rubbing area with steel wool.
(2) Wipe area with clean cloth soaked in alcohol or
similar solvent. It is necessary that all contaminants
be removed from repair area.
(3) Remove package separator clamp and mix plas-
tic conductive epoxy thoroughly.
(4) For grid line, mark off area to be repaired with
masking tape (Fig. 5).
(5) Apply conductive epoxy through slit in masking
tape. Overlap both ends of the break.
Fig. 4 Grid Line Test
1 - VOLTMETER
2 - TERMINAL B
3 - FEED WIRE
4 - MID-POINT C (TYPICAL)
5 - HEATED REAR WINDOW GRIDS
6 - GROUND WIRE
7 - TERMINAL A
RSHEATED GLASS8G-3
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HEATED SEAT SYSTEM
TABLE OF CONTENTS
page page
HEATED SEAT SYSTEM
DESCRIPTION..........................7
OPERATION............................8
DIAGNOSIS AND TESTING - HEATED SEAT
SYSTEM.............................8
DRIVER HEATED SEAT SWITCH
DESCRIPTION..........................8
OPERATION............................8
DIAGNOSIS AND TESTING - DRIVER HEATED
SEAT SWITCH.........................9
REMOVAL.............................10
INSTALLATION.........................10
HEATED SEAT ELEMENTS
DESCRIPTION.........................10
OPERATION...........................10
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENTS..........................10REMOVAL.............................11
INSTALLATION.........................11
HEATED SEAT SENSOR
DESCRIPTION.........................11
OPERATION...........................12
DIAGNOSIS AND TESTING - HEATED SEAT
SENSOR............................12
PASSENGER HEATED SEAT SWITCH
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING - PASSENGER
HEATED SEAT SWITCH.................13
REMOVAL.............................14
INSTALLATION.........................14
HEATED SEAT SYSTEM
DESCRIPTION
Vehicles with the heated seat option can be visu-
ally identified by the two separate heated seatswitches located in the instrument panel center
stack, just above the radio (Fig. 1). The heated seat
system allows the front seat driver and passenger to
select from two different levels of supplemental elec-
trical seat heating (HI/LO), or no seat heating to suit
their individual comfort requirements. The heated
seat system for this vehicle includes the following
major components, which are described in further
detail later in this section:
²Heated Seat Elements- Four heated seat ele-
ments are used per vehicle, two for each front seat.
One heated seat element is integral to each front
seat trim cover, one in the seat back and one in the
seat bottom (cushion). Service replacement heating
elements are available, refer to heated seat elements
later in this section for additional information.
²Heated Seat Modules- Two heated seat mod-
ules are used per vehicle. One module is mounted to
each of the seat cushion pans, located under the for-
ward edge of each front seat. Refer to heated seat
module in the electronic control modules section of
the service manual for additional information.
²Heated Seat Sensors- Two heated seat sen-
sors are used per vehicle, one for each front seat. The
heated seat sensors are integral to each of the heated
seat bottoms (cushions).
²Heated Seat Switch- Two heated seat
switches are used per vehicle, one for the driver and
one for the passenger side front seats. The switches
are mounted in the instrument panel center stack.
Fig. 1 HEATED SEAT SWITCH LOCATIONS
1 - HEATED SEAT SWITCHES
RSHEATED SEAT SYSTEM8G-7
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cator illuminates. When the switch rocker is moved
to its neutral position (middle), Off is selected and
both LED indicators are extinguished.
Each switch provides separate resistor multiplexed
hard wire inputs to its respective Heated Seat Mod-
ule (HSM) to indicate the selected switch position.
The heated seat module responds to the heated seat
switch status messages by controlling the output to
the seat heater elements of the selected seat. The
Low heat position set point is about 36É C (97É F),
and the High heat position set point is about 41É C
(105É F).
DIAGNOSIS AND TESTING - DRIVER HEATED
SEAT SWITCH
For complete circuit diagrams, refer toWiring
Diagrams.
WARNING: REFER TO THE RESTRAINTS SECTION
OF THIS MANUAL BEFORE ATTEMPTING ANY
STEERING WHEEL, STEERING COLUMN, SEAT OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
CHECKING SWITCH SIGNAL AND WIRING AT THE
MODULE
(1) Disconnect and isolate the battery negative
cable.
(2) Access and disconnect the gray 4-way connector
from the heated seat module. Visually inspect wiring
terminals for damage that would prevent positive
connection. If not OK, repair or replace the necessary
components.
(3) Place the heated seat switch in the LO posi-
tion. Using an Ohmmeter, check the resistance
between cavities 2 and 3 of the gray connector noted
above. Resistance should be about 3.5 kilohms (3500
ohms). If not OK, check resistance directly at switch,
as noted below. If OK, proceed to the next step. If not
OK, replace the faulty switch.
(4) Place the heated seat switch in the HI position.
Using an ohmmeter, check the resistance between
cavities 2 and 3 of the gray connector noted above.
Resistance should be about 1.4 kilohms (1400 ohms).
If not OK, check resistance directly at switch, as
noted below. If OK, proceed. If not OK replace the
faulty switch.
(5) With the system ON in the HI position, check
for battery voltage and ground at cavities 4 and 1. If
OK, proceed with testing remaining components. If
not OK, repair open or shorted wiring.
CHECKING SWITCH ONLY
(1) Disconnect and isolate the battery negative
cable. Remove the center bezel from the instrument
panel (Refer to 23 - BODY/INSTRUMENT PANEL/
INSTRUMENT PANEL CENTER BEZEL - REMOV-
AL). Check for continuity between the ground circuit
cavity (#10) of the instrument panel switch bank
electrical connector and a good ground. There should
be continuity. 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. Check for battery
voltage at the fused ignition switch output (run) cir-
cuit cavity of the instrument panel switch bank con-
nector (#4). If OK, turn the ignition switch to the Off
position, and go to Step 3. If not OK, repair the open
fused ignition switch output (run) circuit as required.
(3) Test the heated seat switch as shown in the
Heated Seat Switch Test chart and the connector pin-
out below (Fig. 3). If OK, go to Step 4. If not OK,
replace the faulty switch bank assembly.
DRIVER HEATED SEAT SWITCH TEST
SWITCH
POSITIONRESISTANCE
BETWEENRESISTANCE
(OHMS)
Off Pin4&5OPEN
Low Pin4&53570
High Pin4&51430
All resistance values are  1%.
Fig. 3 Instrument Panel Switch Bank Connector
RSHEATED SEAT SYSTEM8G-9
DRIVER HEATED SEAT SWITCH (Continued)
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(4) Reconnect the instrument panel switch bank
and test the heated seat system for proper operation.
If the system is still inoperative proceed with check-
ing remaining components.
REMOVAL
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO THE RESTRAINTS SECTION OF
THIS MANUAL BEFORE ATTEMPTING ANY STEER-
ING WHEEL, STEERING COLUMN, SEAT OR
INSTRUMENT PANEL COMPONENT DIAGNOSIS OR
SERVICE. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the instrument panel center bezel.
Refer toInstrument Panel Center Bezelin the
Body section for the procedure.
(3) Remove the three screws (Fig. 4) that secure
the heated seat switch to the back of the instrument
panel center bezel.
(4) Remove the heated seat switch from the back
of the instrument panel center bezel.
INSTALLATION
(1) Position the heated seat switch onto the back
of the instrument panel center bezel.
(2) Install and tighten the three screws that secure
the heated seat switch to the back of the instrument
panel center bezel (Fig. 4). Tighten the screws to 1.5
N´m (13 in. lbs.).
(3) Install the center bezel onto the instrument
panel. Refer toInstrument Panel Center Bezelin
the Body section for the procedure.
(4) Reconnect the battery negative cable.
HEATED SEAT ELEMENTS
DESCRIPTION
The heated seat system includes two seat heating
elements in each front seat, one for the seat cushion
and the other for the seat back. The two elements for
each seat that are connected in series with the
Heated Seat Module (HSM). The temperature sensor
is a Negative Temperature Coefficient (NTC) ther-
mistor. One temperature sensor is used for each seat,
and it is located on the seat cushion heating element
for all models.
The seat heating elements are sewn into the seat
cushion cover trim and seat back cover trim units.
The heated seat elements and the temperature sen-
sor cannot be adjusted or repaired and, if faulty or
damaged, the seat element assembly must be
replaced. Refer to the procedure in this section.
OPERATION
The heated seat elements resist the flow of electri-
cal current. When battery current is passed through
the elements, the energy lost by the resistance of the
elements to the current flow is released in the form
of heat. The temperature sensor is a NTC thermistor.
When the temperature of the seat cushion cover
rises, the resistance of the sensor decreases. The
heated seat module supplies a five-volt current to one
side of each sensor, and monitors the voltage drop
through the sensor on a return circuit. The heated
seat module uses this temperature sensor input to
monitor the temperature of the seat, and regulates
the current flow to the seat heating elements accord-
ingly.
DIAGNOSIS AND TESTING - HEATED SEAT
ELEMENTS
The wire harness connectors for the seat cushion
and seat back heating elements are located under the
seat, at the heated seat module. For circuit descrip-
tions and diagrams, refer to section 8W, Wiring Dia-
grams.
Fig. 4 SWITCH RETAINING SCREWS
1 - HEATED SEAT SWITCH ASSEMBLY
2 - RETAINING SCREWS
8G - 10 HEATED SEAT SYSTEMRS
DRIVER HEATED SEAT SWITCH (Continued)
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