sensor DODGE TOWN AND COUNTRY 2001 Repair Manual

REMOVAL - 3.3/3.8L
(1) Release hood latch and open hood.
(2) Disconnect battery negative cable.
(3) Disconnect the push-in field wire connector
from back of generator.
(4) Remove nut holding B+ wire terminal to back
of generator.
(5) Separate B+ terminal from generator.
(6) Raise vehicle and support.
(7) Remove the right front lower splash shield.
(8) Remove accessory drive belt, refer to the Cool-
ing System section for proper procedures.
(9) Remove the lower oil dip stick tube bolt (Fig.
2).
(10) Remove wiring harness from the oil dip stick
tube
(11) Remove the 3 mounting bolts.
(12) Lower vehicle.
(13) Remove oil dip stick tube from vehicle.
(14) Roll and remove the generator from vehicle
(Fig. 3).
INSTALLATION - 2.4L
(1) Install the generator.
(2) Install the accessory drive belt, refer to the
Cooling System section for proper procedures.
(3) Connect B+ terminal to generator.
(4) Install nut holding B+ wire terminal to back of
generator.
(5) Connect the push-in field wire connector to
back of generator.
(6) Install the EVAP Purge solenoid to its bracket.(7) Install the Air Box, refer to the Engine/Air
Cleaner for more information.
(8) Connect the Inlet Air Temperature sensor.
(9) Connect battery negative cable.
INSTALLATION - 3.3/3.8L
(1) Roll and place generator in position on vehicle
(Fig. 3).
(2) Install upper bolts to hold generator in place.
(3) Lubricate the o-ring. Install oil dip stick tube.
(4) Install the upper oil dip stick tube bolt.
(5) Place B+ terminal in position on generator.
(6) Install nut to hold B+ wire terminal to back of
generator.
(7) Connect the push-in field wire connector into
back of generator.
(8) Raise vehicle and support.
(9) Install the lower mounting bolt and tighten.
(10) Install the lower oil dip stick tube bolt and
tighten (Fig. 2).
(11) Install accessory drive belt, refer to the Cool-
ing System section for proper procedures.
(12) Install the right front lower splash shield.
(13) Lower vehicle.
(14) Install wiring harness to the oil dip stick tube
(15) Connect battery negative cable.
(16) Verify generator output rate.
Fig. 2 DIP STICK LOWER BOLT
Fig. 3 GENERATOR 3.3/3.8L
8F - 24 CHARGINGRS
GENERATOR (Continued)
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INSTALLATION
(1) Install the Generator Decoupler to the genera-
tor shaft.
(2) Use Special Tool #8433 (Fig. 6) to tighten the
Generator Decoupler. Refer to the torque chart for
the proper torque.
(3) Install the Air Box, refer to the Engine section
for more information.
(4) Raise vehicle and support.
(5) Install accessory drive belt, refer to the Cooling
System section for proper procedures (Fig. 5).
(6) Install the right front lower splash shield.
(7) Lower vehicle.
(8) Connect battery negative cable.
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 to
control the strength of the rotor magnetic field. The
EVR circuitry monitors system line voltage (B+) and
battery temperature or inlet air temperature sensor
(refer to Battery Temperature Sensor or Inlet Air
Temperature Sensor for more information). It then
determines a target charging voltage. If sensed bat-
tery voltage is 325 mv or lower than the target volt-
age, the PCM grounds the field winding until sensed
battery volage is 325 mv above target voltage. A cir-
cuit in the PCM cycles the ground side of the gener-
ator field up to 250 times per second (250Hz), but
has the capability to ground 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 25% is used by the PCM in
order to have some generator output. Also refer to
Charging System Operation for additional informa-
tion.
REMOVAL
The electronic voltage regulator is not a serviced
separately. If replacement is necessary, the PCM
must be replaced.
Fig. 6 SPECIAL TOOL 8433 AND DECOUPLER
8F - 26 CHARGINGRS
GENERATOR DECOUPLER PULLEY (Continued)
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STARTING
TABLE OF CONTENTS
page page
STARTING
DESCRIPTION...........................27
OPERATION.............................27
DIAGNOSIS AND TESTING.................27
STARTING SYSTEM TEST................27
CONTROL CIRCUIT TEST................29FEED CIRCUIT RESISTANCE TEST.........31
FEED CIRCUIT TEST....................31
SPECIFICATIONS........................32
STARTER MOTOR
REMOVAL..............................33
INSTALLATION...........................34
STARTING
DESCRIPTION
The starting system has (Fig. 1):
²Ignition switch
²Starter relay
²Transmission Range Sensor or Park/Neutral
Switch
²Wiring harness
²Battery
²Starter motor with an integral solenoid
²Powertrain Control Module (PCM)
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.
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:
Fig. 1 Starting System Schematic
1 - SOLENOID TERMINAL
2 - STARTER SOLENOID
3 - STARTER MOTOR
4 - STARTER RELAY CONNECTOR
5 - PCM
6 - GROUND CIRCUIT
7 - TRANSMISSION RANGE SENSOR/PARK/NEUTRAL SENSE
8 - IGNITION SWITCH
9 - IGNITION FEED
10 - BATTERY
11 - BATTERY RELAY FEED
12 - POSITIVE CABLE
13 - NEGATIVE CABLE
RSSTARTING8F-27
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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
the battery, if required. Refer to the Battery section
for more information.
²Ignition Switch- Visually inspect the ignition
switch for indications of physical damage and loose
or corroded wire harness connections.
²Transmission Range Sensor- Visually inspect
the transmission range sensor for indications of phys-
ical damage and loose or corroded wire harness con-
nections.
²Starter Relay- Visually inspect the starter
relay for indications of physical damage and loose or
corroded wire harness connections.²Starter- Visually inspect the starter for indica-
tions of physical damage and loose or corroded wire
harness connections.
²Starter Solenoid- Visually inspect the starter
solenoid for indications of physical damage and loose
or corroded wire harness connections.
²Wiring- Visually inspect the wire harness for
damage. Repair or replace any faulty wiring, as
required. Check for loose or corroded wire harness
connections at main engine ground and remote jump
post.
²Power Distribution Center (PDC)- Visually
inspect the B+ connections at the PDC for physical
damage and loose or corroded harness connections.
STARTING SYSTEM DIAGNOSIS
CONDITION POSSIBLE CAUSE CORRECTION
STARTER FAILS
TO ENGAGE.1. BATTERY
DISCHARGED OR
FAULTY.1. REFER TO THE BATTERYSECTION FOR MORE
INFORMATION. CHARGE OR REPLACE BATTERY, IF
REQUIRED.
2. STARTING CIRCUIT
WIRING FAULTY.2. REFER TO FEED CIRCUIT RESISTANCE TEST AND FEED
CIRCUIT TEST IN THIS SECTION.
3. STARTER RELAY
FAULTY.3. REFER TO RELAY TEST, IN THIS SECTION. REPLACE
RELAY, IF NECESSARY.
4. IGNITION SWITCH
FAULTY.4. REFER TO IGNITION SWITCH TEST, IN THE STEERING
SECTION OR 8 WIRING DIAGRAMS. REPLACE SWITCH, IF
NECESSARY.
5. PARK/NEUTRAL
POSITION SWITCH
(AUTO TRANS) FAULTY
OR MIS-ADJUSTED.5. REFER PARK/NEUTRAL POSITION SWITCH TEST, IN THE
TRANSAXLE. SECTION FOR MORE INFORMATION. REPLACE
SWITCH, IF NECESSARY.
6. CLUTCH PEDAL
POSITION SWITCH
(MAN TRANS) FAULTY.6. REFER TO CLUTCH PEDAL POSITION SWITCH TEST, IN
THE CLUTCH. SECTION. REPLACE SWITCH, IF NECESSARY.
7. STARTER SOLENOID
FAULTY.7. REFER TO SOLENOID TEST, IN THIS SECTION. REPLACE
STARTER ASSEMBLY, IF NECESSARY.
8. STARTER ASSEMBLY
FAULTY.8. IF ALL OTHER STARTING SYSTEM COMPONENTS AND
CIRCUITS CHECK OK, REPLACE STARTER ASSEMBLY.
9. FAULTY TEETH ON
RING GEAR.9. ROTATE FLYWHEEL 360É, AND INSPECT TEETH AND RING
GEAR REPLACED IF DAMAGED.
STARTER
ENGAGES,
FAILS TO TURN
ENGINE.1. BATTERY
DISCHARGED OR
FAULTY.1. REFER TO THE BATTERY SECTION FOR MORE
INFORMATION. CHARGE OR REPLACE BATTERY AS
NECESSARY.
2. STARTING CIRCUIT
WIRING FAULTY.2. REFER TO THE FEED CIRCUIT RESISTANCE TEST AND
THE FEED CIRCUIT TEST IN THIS SECTION. REPAIR AS
NECESSARY.
8F - 28 STARTINGRS
STARTING (Continued)
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CONDITION POSSIBLE CAUSE CORRECTION
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 TEETHAND 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.
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.
(3) Perform a visual inspection of the starter/
starter solenoid for corrosion, loose connections or
faulty wiring.
(4) Locate and remove the starter relay from the
Power Distribution Center (PDC). Refer to the PDC
label for relay identification and location.
RSSTARTING8F-29
STARTING (Continued)
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(5) The coil ground terminal (85) is connected to
the electromagnet in the relay. It is grounded
through the transmission range sensor only when the
gearshift selector lever is in the Park or Neutral
positions. Check for continuity to ground at the cav-
ity for relay terminal 85. If not OK with an auto-
matic transmission, check for an open or short circuit
to the transmission range sensor and repair.
SAFETY SWITCHES
For diagnostics of the Transmission Range Sensor,
refer to the Transaxle section for more information.
If equipped with Clutch Interlock/Upstop Switch,
refer to Diagnosis and Testing in the Clutch section.
IGNITION SWITCH
After testing starter solenoid and relay, test igni-
tion switch and wiring. Refer to the Ignition Section
or Wiring Diagrams for more information. Check all
wiring for opens or shorts, and all connectors for
being loose or corroded.
BATTERY
For battery diagnosis and testing, refer to the Bat-
tery section for procedures.
ALL RELATED WIRING AND CONNECTORS
Refer to Wiring Diagrams for more information.
FEED CIRCUIT RESISTANCE TEST
Before proceeding with this operation, review Diag-
nostic Preparation and Starter Feed Circuit Tests.
The following operation will require a voltmeter,
accurate to 1/10 of a volt.
CAUTION: Ignition and Fuel systems must be dis-
abled to prevent engine start while performing the
following tests.
(1) To disable the Ignition and Fuel systems, dis-
connect the Automatic Shutdown Relay (ASD). The
ASD relay is located in the Power Distribution Cen-
ter (PDC). Refer to the PDC cover for proper relay
location.
(2) Remove the air cleaner assembly for access to
battery terminals. Refer to the Fuel section for ser-
vice procedures.
(3) With all wiring harnesses and components
properly connected, perform the following:
(a) Connect the negative lead of the voltmeter to
the battery negative post, and positive lead to the
battery negative cable clamp. Rotate and hold the
ignition switch in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between cable clamp and post.(b) Connect positive lead of the voltmeter to the
battery positive post, and negative lead to the bat-
tery positive cable clamp. Rotate and hold the igni-
tion switch key in the START position. Observe the
voltmeter. If voltage is detected, correct poor con-
tact between the cable clamp and post.
(c) Connect negative lead of voltmeter to battery
negative terminal, and positive lead to engine
block near the battery cable attaching point.
Rotate and hold the ignition switch in the START
position. If voltage reads above 0.2 volt, correct
poor contact at ground cable attaching point. If
voltage reading is still above 0.2 volt after correct-
ing poor contacts, replace ground cable.
(4) Connect positive voltmeter lead to the starter
motor housing and the negative lead to the battery
negative terminal. Hold the ignition switch key in
the START position. If voltage reads above 0.2 volt,
correct poor starter to engine ground.
(a) Connect the positive voltmeter lead to the
battery positive terminal, and negative lead to bat-
tery cable terminal on starter solenoid. Rotate and
hold the ignition switch in the START position. If
voltage reads above 0.2 volt, correct poor contact at
battery cable to solenoid connection. If reading is
still above 0.2 volt after correcting poor contacts,
replace battery positive cable.
(b) If resistance tests do not detect feed circuit
failures, replace the starter motor.FEED CIRCUIT TEST
NOTE: The following results are based upon the
vehicle being at room temperature.
The following procedure will require a suitable
volt-ampere tester (Fig. 2).
CAUTION: Before performing any starter tests, the
ignition and fuel systems must be disabled.
Fig. 2 Volt Ampere Tester
RSSTARTING8F-31
STARTING (Continued)
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OPERATION
The Rear Window Defogger (Fig. 1) system consists
of two vertical bus bars linked by a series of grid
lines on the inside surface of the rear window. The
electrical circuit consists of the rear defogger switch
in the HVAC control assembly and a relay with timer
switch to turn OFF the system after ten minutes.
The main feed circuit is protected by fuse 13 (40
amp) in the Power Distribution Center (PDC) which
is integrated as a unit call Integrated Power Module
(IPM). The rear defogger switch and relay also acti-
vates the heated power side view mirrors and heated
windshield wiper de-icer. The heated windshield
wiper de-icer is powered by the RUN/ACC relay in
the IPM and feed thru fuse #11 (20 amp) in the PDC.
The heated mirror circuit is protected by a non-servi-
cable Positive Temperature Coefficient (PTC) located
inside the PDC. The heated windshield wiper de-icer
circuit is protected by fuse 11 (20 amp) in the PDC.
The Heated Windshield Wiper Deicer is also acti-
vated when the DEFROST mode is selected on the
HVAC. In the DEFROST mode the rear defogger
relay/timer is bypassed, the heated windshield wiper
de-icer will stay ON until the another mode is
selected. For circuit information and component loca-
tion refer to appropriate section for Wiring Diagrams.
CAUTION:
Since grid lines can be damaged or scraped off
with sharp instruments, care should be taken in
cleaning the glass or removing foreign materials,
decals or stickers. Normal glass cleaning solvents
or hot water used with rags or toweling is recom-
mended.
DEFOGGER RELAY
DESCRIPTION
There is no heated glass relay it is integrated into
the (E.B.L) relay that is located in the IPM in the
engine compartment.
REAR WINDOW DEFOGGER
GRID
STANDARD PROCEDURE - GRID LINE
REPAIR-REAR
For Grid repair procedure for the rear window
defogger (Refer to 8 - ELECTRICAL/HEATED
GLASS/WINDSHIELD GRID - STANDARD PROCE-
DURE).
REAR WINDOW DEFOGGER
SWITCH
DESCRIPTION
The rear window defogger switch is integrated into
the HVAC control panel assembly (Fig. 3)
OPERATION
A LED indicator will illuminate when the switch is
activated. The switch energizes the HVAC control
assembly when it requests the Front Control Module
(FCM) to activate the rear window defogger relay.
The relay controls the current to flow to the grids of
the rear window defogger, heated power side view
mirrors and the heated windshield wiper de-icer. The
defogger relay will be on for approximately 10 min-
utes or until the control switch or ignition is turned
off.
Fig. 3 HVAC CONTROL PANEL
1 - Trim Bezel
2 - ACT Sensor
3 - A/C Request Switch
4 - Rear Window Defogger/Heated Mirrors Switch Combo
5 - Front Window Defroster Mode Selector
8G - 2 HEATED GLASSRS
HEATED GLASS (Continued)
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HEATED MIRRORS
TABLE OF CONTENTS
page page
HEATED MIRRORS
DESCRIPTION............................5
OPERATION.............................5
DIAGNOSIS AND TESTING..................5
HEATED MIRROR TEST...................5
MIRROR SWITCH
DESCRIPTION............................5OPERATION.............................5
HEATED MIRROR GRID
STANDARD PROCEDURE...................6
HEATED MIRROR.......................6
RELAY
DESCRIPTION............................6
HEATED MIRRORS
DESCRIPTION
Heated mirrors are available on models with
Power Mirrors and Rear Window Defogger only.
OPERATION
The heated mirror is controlled by the rear window
defogger switch. The heated mirror is ON when the
rear window defogger is ON (Fig. 1)
DIAGNOSIS AND TESING - HEATED MIRROR
TEST
Heated mirrors are available on models with
Power Mirrors and Rear Window Defogger only. The
heated mirror is controlled by the rear window defog-
ger switch. The heated mirror is ON when the rear
window defogger is ON.
(1) The mirror glass should be warm to the touch.
(2) If not, check the 20 amp fuse (11) in the Power
Distribution Center (PDC) part of the Integrated
Power Module (IPM) in the engine compartment.
(3) Test voltage at rear window defogger switch.
²If no voltage repair wire.
²Remove mirror glass and test the wires for con-
tinuity. If no continuity repair wires.
²If wires are OK, replace mirror glass.
²To test defogger switch refer to the appropriate
section in Electrical.
MIRROR SWITCH
DESCRIPTION
The heated mirror switch is integrated into the
rear window defogger switch located in the HVAC
control panel (Fig. 1)
OPERATION
A LED indicator will illuminate when the switch is
activated. The switch energizes the HVAC control
assembly when it requests the Front Control Module
(FCM) to activate the rear window defogger relay.
The relay controls the current to flow to the grids of
the rear window defogger, heated power side view
mirrors and the heated windshield wiper de-icer. The
defogger relay will be on for approximately 10 min-
utes or until the control switch or ignition is turned
off.
Fig. 1 HVAC CONTROL PANEL
1 - Trim Bezel
2 - ACT Sensor
3 - A/C Request Switch
4 - Rear Window Defogger/Heated Mirrors Switch Combo
5 - Front Window Defroster Mode Selector
RSHEATED MIRRORS8G-5
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HEATED SEAT SYSTEM
TABLE OF CONTENTS
page page
HEATED SEAT SYSTEM
DESCRIPTION............................7
OPERATION.............................8
DRIVER HEATED SEAT SWITCH
DESCRIPTION............................8
OPERATION.............................9
DIAGNOSIS AND TESTING..................9
HEATED SEAT SWITCH...................9
REMOVAL..............................10
INSTALLATION...........................10
HEATED SEAT ELEMENT
DESCRIPTION...........................10
OPERATION.............................11DIAGNOSIS AND TESTING.................11
HEATED SEAT ELEMENT.................11
HEATED SEAT SENSOR
DESCRIPTION...........................11
DIAGNOSIS AND TESTING.................11
HEATED SEAT SENSOR..................11
PASSENGER HEATED SEAT SWITCH
DESCRIPTION...........................11
OPERATION.............................11
DIAGNOSIS AND TESTING.................12
HEATED SEAT SWITCH..................12
REMOVAL..............................13
INSTALLATION...........................13
HEATED SEAT SYSTEM
DESCRIPTION
Individually controlled driver and passenger side
electrically heated front seats are available factory-
installed optional equipment on this model, when it
is also equipped with the power seat option. The
heated seat system allows both the driver and the
front seat passenger the option to select one of twoseat heating ranges, Low or High, or to turn the indi-
vidual seat heaters Off using the heated seat
switches located in the instrument panel center bezel
near the bottom of the HVAC outlets (Fig. 1). The
heated seat switch circuit operates on ignition
switched battery current supplied through a fuse in
the intelligent power module, only when the ignition
switch is in the On position.
This section covers the following components of the
heated seat system:
²Heated seat elements
²Heated seat sensors
²Heated seat switches
The Heated seat module (or memory heated seat
module) can be found in the Electronic Control Mod-
ules section of the service manual.
The heated seat system also relies upon resources
shared with other electronic modules in the vehicle
over the Programmable Communications Interface
(PCI) J1850 data bus network. The J1850 (PCI) data
bus network allows the sharing of sensor informa-
tion. This helps to reduce wire harness complexity,
internal controller hardware, and component sensor
current loads. At the same time, this system provides
increased reliability, enhanced diagnostics, and
allows the addition of many new feature capabilities.
For diagnosis of these electronic modules or of the
J1850 (PCI) data bus network, the use of a DRB IIIt
scan tool, or equivalent and the proper Diagnostic
Procedures manual are recommended.
The electronic modules that may affect heated seat
system operation are as follows:
²Body Control Module (BCM)- Refer toBody
Control Modulein Electronic Control Modules for
more information.
Fig. 1 HEATED SEAT SWITCHES
RSHEATED SEAT SYSTEM8G-7
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²Remote Keyless Entry Module (RKE)- Refer
toRemote Keyless Entry Modulein Power Locks
for more information.
²Electronic Vehicle Information Center
(EVIC)- Refer toElectronic Vehicle Information
Centerin Overhead Console for more information.
²Heated Seat Module (HSM)- Refer toHeated
Seat Modulein Electronic Control Modules for more
information.
²Memory Heated Seat Module (MHSM)-If
the vehicle is equipped with the Memory System,
refer toMemory Seat Mirror Module (MSMM)in
Electronic Control Modules for more information.
Refer toWiring Diagramsfor complete circuit
diagrams. Following are general descriptions of the
major components in the heated seat system.
OPERATION
The heated seat system will only operate when the
ignition switch is in the On position, and the surface
temperature at the front seat heating element sen-
sors is below the designed temperature set points of
the system. The heated seat system will not operate
in ambient temperatures greater than about 41É C
(105É F). The front seat heating elements and sensors
are hard wired to the Heated Seat Module (HSM) or
the Memory Heated Seat Module (MHSM).
The heated seat switches are hard wired to the
Body Control Module (BCM). The BCM monitors the
heated seat switch inputs, then sends heated seat
switch status messages to the HSM or MHSM over
the Programmable Communications Interface J1850
(PCI) data bus. The HSM or MHSM contains the con-
trol logic for the heated seat system. The HSM or
MHSM responds to the heated seat switch status
messages, ignition switch status messages, and the
front seat heating element sensor inputs by control-
ling the output to the front seat heating elements
through integral solid-state relays.
When a seat heater is turned on, the sensor
located on the seat cushion electric heater element
provides the HSM or MHSM with an input indicating
the surface temperature of the seat cushion. If the
surface temperature input is below the temperature
set point for the selected Low or High heated seat
switch position, the HSM or MHSM energizes the
integral solid-state relay, which supplies battery cur-
rent to the heating elements in the seat cushion and
back. When the sensor input indicates the correct
temperature set point has been achieved, the HSM or
MHSM de-energizes the solid-state relay. The HSM
or MHSM will continue to cycle the solid-state relay
as needed to maintain the temperature set point.
The HSM or MHSM and the seat heater elements
operate on non-switched battery current supplied
through the power seat fuse in the intelligent powermodule. However, the HSM or MHSM will automati-
cally turn off the heating elements if it detects an
open in the sensor circuit, a short in the heating ele-
ment circuit causing an excessive current draw, or
when the ignition switch is turned to the Off posi-
tion.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the heated seat system.
DRIVER HEATED SEAT
SWITCH
DESCRIPTION
The heated seat switches are mounted in the
instrument panel center bezel (Fig. 2). The two three-
position rocker-type switches, one switch for each
front seat, are incorporated into one large switch
assembly that also includes the hazzard, rear window
wiper and washer switches. The heated seat switches
provide a resistor multiplexed signal to the Body
Control Module (BCM) through separate hard wired
circuits. Each switch has an Off, Low, and High posi-
tion so that both the driver and the front seat pas-
senger can select a preferred seat heating mode.
Each switch has two Light-Emitting Diodes (LED)
which light to indicate that the heater for the seat is
turned on.
The heated seat switches and their LEDs cannot
be repaired. If either switch or LED is faulty or dam-
aged, the entire switch assembly must be replaced.
Fig. 2 HEATED SEAT SWITCHES
8G - 8 HEATED SEAT SYSTEMRS
HEATED SEAT SYSTEM (Continued)
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