light CHRYSLER CARAVAN 2005 Workshop Manual

PARK ASSIST SYSTEM
The Park Assist System display activates an audi-
ble tone that changes from intermittent to continu-
ous as the final two Light Emitting Diodes (LED's)
are illuminated on one side or both sides of the dis-
play.
The system detection length from the rear of the
vehicle is 0.3 meters to 1.5 meters. This area extends
around the rear side of the vehicle. The system detec-
tion height from the ground is 0.2 meters to about
1.5 meters. The radio mutes when the system acti-
vates its audible tone.
When the driver selects Reverse the system scans
for objects behind the vehicle using four sensors
located in the rear bumper. A warning display above
the rear window provides both visible and audible
warnings indicating the range of the object.
The system is active only when the transmission
gear selector is in reverse for vehicle speeds less than
16 Km/h (10 mph). If the vehicle's Parking/Emer-
gency Brake is applied, the system is deactivated.
The display contains two sets of yellow and red
Light Emitting Diode's (LED's) that the driver can
see as they look over their shoulder while backing
up. Each side of the vehicle has its own warning
LED's. The system provides a visual warning by illu-
minating one or more yellow LED's as the vehicle
gets closer to the object. As the vehicle continues to
approach the object, one red LED is illuminated and
the system emits a series of short beeps. The tone
will remain constant and both red LED's are illumi-
nated once the vehicle is within 12 inches (30.5 cm)
of the object.
The system can be turned ON or OFF through the
Electronic Vehicle Information Center (EVIC) when
the vehicle is in PARK. If the park assist system is
turned OFF, a single chime will sound and the EVIC
will display the following message ªREAR PARK
ASSIST OFFº, when the vehicle is in reverse.
²Ensure that the rear bumper is free of dirt and
debris to keep the system operating properly.
²Jackhammers, large trucks, and other vibrations
could affect the performance of the system.
²Ensure that the parking brake is not applied.
If ªService Park Assist Systemº appears in the
EVIC after making sure the rear bumper is clean,
proceed to diagnose the system using a scan tool and
the appropriate diagnostic information.
WARNING
On vehicles equipped with airbags, disable
the airbag system before attempting any steer-
ing wheel, steering column, or instrument
panel component diagnosis or service. Discon-
nect and isolate the battery negative (ground)
cable, then wait two minutes for the airbag sys-
tem capacitor to discharge before performing
further diagnosis or service. This is the only
sure way to disable the airbag system. Failure
to take the proper precautions could result in
accidental airbag deployment, personal injury,
or death.
DIAGNOSIS AND TESTING - CHIME SYSTEM
Refer to the proper Body Diagnostic Procedures
manual for complete Diagnosis and Testing of the
Chime System.
NO TONE WHEN IGNITION SWITCH IS TURNED ON
AND DRIVER'S SEAT BELT IS NOT BUCKLED.
(1) Using a DRB llltscan tool, actuate chime
(BCM actuates).
(2) Using a voltmeter, check for voltage:
(a) BCM has two battery feeds at pin 1 and pin
5 of the 6±way connector.
(b) Pin 5 of the (BX2) 32 way connector of the
BCM for ignition feed.
(c) Check voltage (PX2) connector, pin 34 for 12v.
(d) If voltage OK, go to step Step 3
(e) If NO voltage repair as necessary. Refer to
the appropriate wiring information. The wiring
information includes wiring diagrams, proper wire
and connector repair procedures, further details on
wire harness routing and retention, as well as pin-
out and location views for the various wire harness
connectors, splices and grounds.
(3) Check drivers seat belt buckle switch input
(from Occupant Restraint Controller (ORC) for a
closed circuit when not buckled. If input not seen,
look for open in wiring or switch. The switch is
grounded when belt is not buckled.
(4) Verify Programmable Communication Interface
(PCI) data bus communication between ORC and
BCM.
8B - 2 CHIME/BUZZERRS
CHIME/BUZZER (Continued)

NO FASTEN SEAT BELT LAMP WHEN IGNITION
SWITCH IS TURNED ON.
(1) Check for burned out lamp.
(2) Using a voltmeter check for voltage at the clus-
ter connector:
(a) Pin 2 of the mechanical instrument cluster
for battery feed.
(b) Pin 11 of the mechanical instrument cluster
for ignition voltage.
(3) Repair as necessary.
FASTEN SEAT BELT LAMP OR TONE CONTINUES
FOR MORE THAN 10 SECONDS AFTER SEAT
BELTS ARE FASTENED AND DRIVER'S DOOR IS
CLOSED.
Refer to the proper Body Diagnostic Procedures
manual.
NO TONE WHEN PARK OR HEADLAMPS ARE ON
AND DRIVER'S DOOR IS OPEN.
Make sure ignition is in lock position with the key
removed.
(1) Check the BCM DTC's and BCM sensors to
verify the door is open. Repair as necessary.
(2) Actuate Chime (BCM actuates).
(3) Inspect BCM connectors and wires for proper
connection.
(4) Measure with a voltmeter the voltage (12v) on
BCM connector (PX2) pin 34 with harness connected.
(5) Check BCM sensors to verify headlamp switch
position.
PARK ASSIST DISPLAY
DESCRIPTION
The Park Assist Display is located in the rear of
vehicle, over the rear window in the headliner (Fig.
1). It is a molded plastic unit housing Light Emitting
Diodes (LED's) and a chime module. Located in the
rear of the vehicle for easy visual reference when the
driver is backing up.
The display is used to alert the driver of any obsta-
cles detected in the rear of the vehicle. The chime or
audible signal also comes from the display unit.
OPERATION
When the ignition is put in the RUN position, all
the Light Emitting Diodes (LED's) will illuminate for
approximately one second. This will be interrupted if
the system senses an obstacle.
The ready status will be sensed by the outermost
two yellow LED's being illuminated at 50% intensity.
As the obstacle is sensed, the yellow LED's will start
illuminating inward until the object in approximately
one foot away and then the inner red LED will light.
The display is sensitive to which side of the rear of
the vehicle that the object is detected. If on the left
rear, the left segments will light and the same for the
right side of the vehicle.
Fig. 1 PARK ASSIST DISPLAY
RSCHIME/BUZZER8B-3
CHIME/BUZZER (Continued)

²System diagnostics - diagnosis and error han-
dling (sensors, display, module).
²Data exchange over the Programmable Commu-
nication Interface (PCI) data bus.
OPERATION
The module has a number of functions:
²Supply voltage to the sensors and display.
²Disconnection of the display with bus idle and
over voltage Vmax.
²Triggering the sensors.
²Analyze echo delay times and calculate obstacle
distances.
²Bi-directional data communication to the display
for diagnosis.
²System diagnostics - diagnosis and error han-
dling (sensors, display, module).
²Data exchange over the Programmable Commu-
nication Interface (PCI) data bus.
The system detection length from the rear of the
vehicle is 0.3 meters to 1.5 meters. This area extends
around the rear side of the vehicle. The system detec-
tion height from the ground is 0.2 meters to about
1.5 meters. The radio mutes when the system acti-
vates its audible tone.When the driver selects Reverse, the system scans
for objects behind the vehicle using four sensors
located in the rear bumper. Objects can be detected
from up to 1.5 meters. A warning display above the
rear window provides both visible and audible warn-
ings indicating the range of the object.
The system is active only when the vehicle is in
reverse for vehicle speeds less than 16 Km/h (10
mph). If the vehicles Parking/Emergency Brake is
applied, the system is deactivated.
The display contains two sets of yellow and red
Light Emitting Diode's (LED's) that the driver can
see as they look over their shoulder while backing
up. Each side of the vehicle has its own warning
LED's. The system provides a visual warning by illu-
minating one or more yellow LED's as the vehicle
gets closer to the object. As the vehicle continues to
approaches the object, one red LED is illuminated
and the system emits a series of short beeps. The
tone will remain constant and both red LED's are
illuminated once the vehicle is within 12 inches (30.5
cm) of the object.
The system can be turned ON or OFF through the
Electronic Vehicle Information Center (EVIC) when
the vehicle is in PARK. If the park assist system is
turned OFF, a single chime will sound and the EVIC
will display the following message ªREAR PARK
ASSIST OFFº, when the vehicle is in reverse.
²Ensure that the rear bumper is free of dirt and
debris to keep the system operating properly.
²Jackhammers, large trucks, and other vibrations
could affect the performance of the system.
²Ensure that the parking brake is not applied.
If ªService Park Assist Systemº appears in the
EVIC after making sure the rear bumper is clean,
proceed to diagnose the system using a scan tool and
the appropriate diagnostic information.
To diagnose the Park Assist Module, use a scan
tool and the appropriate body diagnostic information.
REMOVAL
(1) Open hood.
(2)
Disconnect and isolate the battery negative cable.
(3) Remove the left quarter trim panel (Refer to 23
- BODY/INTERIOR/QUARTER TRIM PANEL -
REMOVAL).
Fig. 3 PARK ASSIST MODULE - LOCATION
1 - RETAINING SCREW J-CLIPS
2 - LEFT QUARTER PANEL/C-PILLAR
3 - MODULE RETAINING SCREWS
4 - PARK ASSIST MODULE
RSCHIME/BUZZER8B-5
PARK ASSIST MODULE (Continued)

The BCM utilizes integrated circuitry and informa-
tion carried on the Programmable Communications
Interface (PCI) data bus network along with many
hard wired inputs to monitor many sensor and
switch inputs throughout the vehicle. In response to
those inputs, the internal circuitry and programming
of the BCM allow it to control and integrate many
electronic functions and features of the vehicle
through both hard wired outputs and the transmis-
sion of electronic message outputs to other electronic
modules in the vehicle over the PCI data bus.
OPERATION
The Body Control Module (BCM) supplies vehicle
occupants with visual and audible information and
controls various vehicle functions. To provide and
receive information, the BCM is interfaced to the
vehicle's serial bus communications network, referred
to as the Programmable Communications Interface
(PCI) bus.
This network consists of the;
²Powertrain Control Module (PCM)
²Transmission Control Module (TCM)
²Mechanical Instrument Cluster (MIC)
²Occupant Restraint Controller (ORC)
²Compass/Mini-Trip Computer (CMTC)
²Electronic Vehicle Information Center (EVIC)
²Controller Antilock Brake (CAB)
²HVAC Control Module
²Sliding Door Control Modules (driver and pas-
senger side doors)
²Power Liftgate Module (PLG)
²Audio system equipped with RAZ, RBU, RBK,
and RBB radios.
²Sentry Key Remote Entry Module (SKREEM).
²Side Impact Airbag Control Module (SIACM)²Memory Seat Module (MSM)
²Sentry Key Immobilizer Module (SKIM)
The BCM is operational when battery power is
supplied to the module.
The BCM provides the following features:
²Power Door Locks
²Automatic Door Locks
²Battery Protection - The BCM will automatically
turn off all exterior lamps after 3 minutes, and all
interior lamps after 15 minutes after the ignition is
turned off, if they are not turned off by the driver.
²Chime Control
²Compass/Mini-Trip support.
²Interior Lighting (Courtesy/Reading Lamps)
²BCM Diagnostic Reporting
²Electronic Liftgate Release (with Power Door
Locks)
²Exterior Lighting
²Headlamp Time Delay (with/without Automatic
Headlamps)
²Illuminated Entry
²Fade to Off Interior Lamps - This feature dims
the interior lighting (courtesy lamps) gradually if the
BCM does not receive any new inputs that would
cause the interior lamps to remain on.
²Pulse Width Modulated Instrument Panel Dim-
ming
²Door Lock Inhibit - This feature disables the
door lock functions if the key is in the ignition and
either front door is ajar. Pressing the Remote Keyless
Entry (RKE) lock/unlock button under these condi-
tions result in normal lock/unlock activation.
The BCM has the ability to LEARN additional fea-
tures in the vehicle, provided the appropriate switch
input and PCI data bus messages are received. Refer
to the LEARNED FEATURES table.
LEARNED FEATURES
FEATURE LEARNING KEY
REAR WIPER CONTROL ON HVAC CONTROL ON
INSTRUMENT PANELPCI BUS MESSAGE RECEIVED FROM HVAC
CONTROL
AUTOMATIC HEADLAMPS PCI MESSAGE FROM OVERHEAD OR HEADLAMP
SWITCH POSITION (AUTO)
REMOTE KEYLESS ENTRY SKREEM MESSAGE RECEIVED FROM MODULE
FRONT FOG LAMPS HEADLAMP SWITCH POSITION (PARK W/FRONT
FOG LAMPS)
POWER SLIDING DOOR PCI IFR RECEIVED FROM MODULE
THE BCM HAS FOUR SWITCH INPUTS FOR THE POWER SLIDING DOOR FEATURE; LOCATED IN THE
OVERHEAD CONSOLE ARE THE LEFT AND RIGHT SIDE SLIDING DOOR SWITCHES TO ACTIVATE EITHER
OR BOTH SLIDING DOORS UNDER THE PROPER CONDITIONS. ALSO ARE B-PILLAR SWITCHES LOCATED
ON THE LEFT AND RIGHT B-PILLAR POSTS.
POWER LIFTGATE PCI IFR RECEIVED FROM MODULE
RSELECTRONIC CONTROL MODULES8E-3
BODY CONTROL MODULE (Continued)

FRONT CONTROL MODULE
DESCRIPTION
The Front Control Module (FCM) is a micro con-
troller based module located in the engine compart-
ment. The FCM mates to the Power Distribution
Center (PDC) to form the Integrated Power Module
(IPM). The IPM connects directly to the battery and
provides the primary means of circuit protection and
power distribution for all vehicle electrical systems.
The FCM controls power to some of these vehicle sys-
tems electrical and electromechanical loads based on
inputs received from hard wired switch inputs and
data received on the Programmable Communications
Interface (PCI) data bus.
For information on the IPM, (Refer to 8 - ELEC-
TRICAL/POWER DISTRIBUTION/INTEGRATED
POWER MODULE - DESCRIPTION)
OPERATION
As messages are sent over the Programmable Com-
munications Interface (PCI) data bus, the Front Con-
trol Module (FCM) reads these messages and controls
power to some of the vehicles electrical systems by
completing the circuit to ground (low side driver) or
completing the circuit to 12 volt power (high side
driver).
The following functions arecontrolledby the
Front Control Module:
²Accessory Relay Actuation
²Brake Transmission Shift Interlock Functions
(BTSI - gas engine only)
²Diesel Cabin Heater (Diesel Engine Vehicles)
²Electronic Back Light (EBL) Rear Defogger
²Front and Rear Blower Motor Relay Actuation
²Front Fog Lamp Relay Actuation
²Washer Motor (front and rear)
²Front Windshield Wiper ªHIº & ªLOº Relay
Actuation
²Front Windshield Wiper ªONº Relay Actuation
²Headlamp Power with Voltage Regulation
²Horn Relay Actuation
²Headlamp Washer Relay Actuation (IF
EQUIPPED - EXPORT ONLY)
²Name Brand Speaker (NBS) Relay Actuation
²Park Lamp Relay Actuation
The following inputs areReceived/Monitoredby
the Front Control Module:
²Ambient Temperature Sensing
²Back-Up switch
²Brake Fluid Level
²B+ Connection Detection
²Engine Crank Signal (Diesel Engine Vehicles)
²Horn Input
²Ignition Switch Start Only
²Ignition Switch Run and Start Only²Stop Lamp Sense
²Washer Fluid Level
²Windshield Wiper Park
DIAGNOSIS AND TESTING
FRONT CONTROL MODULE
The Front Control Module (FCM) is a printed cir-
cuit board based module with a on-board micro-pro-
cessor. The FCM interfaces with other electronic
modules in the vehicle via the Programmable Com-
munications Interface (PCI) data bus. In order to
obtain conclusive testing the PCI data bus and all of
the electronic modules that provide inputs to, or
receive outputs from the FCM must be checked. All
PCI communication faults must be resolved prior to
further diagnosing any front control module related
issues.
The FCM was designed to be diagnosed with an
appropriate diagnostic scan tool, such as the DRB
IIIt. The most reliable, efficient, and accurate means
to diagnose the front control module requires the use
of a DRB IIItscan tool and the proper Body Diag-
nostic Procedures manual.
Before any testing of the FCM is attempted, the
battery should be fully charged and all wire harness
and ground connections inspected around the affected
areas on the vehicle.
REMOVAL
(1) Disconnect and isolate the negative and posi-
tive battery cables from the battery.
(2) Remove the battery (Refer to 8 - ELECTRI-
CAL/BATTERY SYSTEM/BATTERY - REMOVAL).
(3) Using a long flat-bladed screwdriver, gently
twist the Integrated Power Module (IPM) retaining
clip outboard to free the IPM from its mounting
bracket (Fig. 5). Rotate IPM upward to access the
Front Control Module (FCM) retaining screws.
(4) Remove the front control module retaining
screws.
(5) Pull the FCM straight from the IPM assembly
to disconnect the electrical connector (Fig. 6) and
remove the FCM from the vehicle.
INSTALLATION
NOTE: Front Control Module must be programmed
to the correct radio EQ curve using the DRB IIIT.
This will ensure that the audio system is operating
correctly.
(1) Install the Front Control Module (FCM) in the
Integrated Power Module (IPM) assembly by pushing
the 49-way electrical connector straight in.
RSELECTRONIC CONTROL MODULES8E-7

ULES/POWERTRAIN CONTROL MODULE -
DESCRIPTION) section for more DTC information.
The Charging system ªBatteryº light indicates
problems with the charging system (voltage too high/
low, generator failure, etc.). If an extreme condition is
indicated, the lamp will be illuminated. 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 infor-
mation.
The PCM uses the ambient air temperature sensor
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 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.
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 DTC
to 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
Diagnostic manual 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.
(4) Inspect generator mounting bolts for tightness.
Replace or tighten bolts if required. Refer to the Gen-
erator Removal/Installation section of this group for
8F - 22 CHARGINGRS
CHARGING (Continued)

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.
DIAGNOSIS AND TESTING - 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. 1).
CAUTION: Before performing any starter tests, the
ignition and fuel systems must be disabled.(1) Check battery before performing this test. Bat-
tery must be fully charged.
(2) Connect a volt-ampere tester to the battery ter-
minals. Refer to the operating instructions provided
with the tester being used.
(3) 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.
(4) Verify that all lights and accessories are OFF,
and the transmission shift selector is in the PARK
and SET parking brake.
CAUTION: Do not overheat the starter motor or
draw the battery voltage below 9.6 volts during
cranking operations.
(5) Rotate and hold the ignition switch in the
START position. Observe the volt-ampere tester (Fig.
1).
²If voltage reads above 9.6 volts, and amperage
draw reads above 280 amps, check for engine seizing
or faulty starter.
²If voltage reads 12.4 volts or greater and amper-
age reads 0 to 10 amps, check for corroded cables
and/or bad connections.
²Voltage below 9.6 volts and amperage draw
above 300 amps, the problem is the starter. Replace
the starter refer to starter removal.
(6) After the starting system problems have been
corrected, verify the battery state-of-charge and
charge battery if necessary. Disconnect all testing
equipment and connect ASD relay. Start the vehicle
several times to assure the problem has been cor-
rected.
SPECIFICATIONS
Torques
DESCRIPTION N´m Ft. Lbs. In. Lbs.
Starter Mounting Bolts 47.4 35
Starter Solenoid Battery
Nut11.3 8.3 100
Fig. 1 Volt Ampere Tester
8F - 36 STARTINGRS
STARTING (Continued)

HEATED SYSTEMS
TABLE OF CONTENTS
page page
HEATED GLASS........................... 1
HEATED MIRRORS......................... 6HEATED SEAT SYSTEM..................... 7
HEATED GLASS
TABLE OF CONTENTS
page page
HEATED GLASS
DESCRIPTION..........................1
OPERATION............................2
DIAGNOSIS AND TESTING
ELECTRIC BACKLIGHT (EBL) SYSTEM.....2
REAR WINDOW DEFOGGER RELAY
DESCRIPTION..........................3
OPERATION............................3REMOVAL.............................4
INSTALLATION..........................4
REAR WINDOW DEFOGGER SWITCH
DESCRIPTION..........................4
OPERATION............................4
REAR WINDOW DEFOGGER GRID
STANDARD PROCEDURE
GRID REPAIR PROCEDURE..............5
HEATED GLASS
DESCRIPTION
CAUTION: Grid lines can be damaged or scraped
off with sharp instruments. Care should be taken in
cleaning glass or removing foreign materials,
decals or stickers. Normal glass cleaning solvents
or hot water used with rags or toweling is recom-
mended.
The rear window defogger system, also known as
electrical backlight (EBL), consists of two vertical bus
bars linked by a series of grid lines fired onto the
inside surface of the rear window (Fig. 1).
The EBL system is turned ON or OFF by a control
switch located on the A/C-heater control at the center
of the instrument panel and by a rear window defog-
ger relay timing circuit integral to the integrated
power module (IPM) (Refer to 8 - ELECTRICAL/
HEATED GLASS/REAR WINDOW DEFOGGER
SWITCH - DESCRIPTION).
Circuit protection is provided by a 40 amp fuse
located in the IPM.
Fig. 1 Rear Window Defogger - Typical
1 - REAR DEFOGGER GRID
2 - REAR WINDOW
RSHEATED SYSTEMS8G-1

OPERATION
When the rear window defogger button is
depressed to the On position, current is directed to
the rear defogger grid lines and the heated power
mirrors (if equipped). The heated grid lines heat the
glass to help clear the rear window and side mirror
surfaces of fog or frost.
The electric backlight (EBL) system is controlled
by a momentary switch located in the A/C-heater
control on the instrument panel. A yellow indicator in
the switch will illuminate to indicate when the sys-
tem is turned on. The integrated power module (IPM)
contains the EBL system control circuitry.
NOTE: The rear window defogger turns off automat-
ically after approximately 10 minutes of initial oper-
ation. Each following activation cycle of the
defogger system will last approximately five min-
utes.
The EBL system will be automatically turned off
after a programmed time interval of about ten min-
utes. After the initial time interval has expired, if the
defogger switch is turned on again during the same
ignition cycle, the defogger system will automatically
turn off after about five minutes.
The EBL system will automatically shut off if the
ignition switch is turned to the Off position, or it can
be turned off manually by depressing the defogger
switch a second time.
DIAGNOSIS AND TESTING
ELECTRIC BACKLIGHT (EBL) SYSTEM
NOTE: Illumination of the defogger switch indicator
lamp means that there is electrical current available
at the output of the rear window defogger logic cir-
cuitry, but does not confirm that the electrical cur-
rent is reaching the rear glass heating grid lines.
NOTE: For circuit descriptions and diagrams of the
rear window defogger system, refer to 8W - WIRING
DIAGRAM INFORMATION.
Operation of the electrical backlight (EBL) system
can be confirmed by the following:(1) Turn the ignition switch to the On position. Set
the defogger switch in the On position. The rear win-
dow defogger operation can be checked by feeling the
rear window glass. A distinct difference in tempera-
ture between the grid lines and the adjacent clear
glass can be detected within three to four minutes of
operation.
(2) If a temperature difference is not detected, use
a 12-volt DC voltmeter and contact the rear glass
heating grid terminal B with the negative lead, and
terminal A with the positive lead (Fig. 2). The volt-
meter should read battery voltage. If the voltmeter
does not read battery voltage, check the following:
²Confirm that the ignition switch is in the On
position.
²Make sure that the rear glass heating grid feed
wire and ground wire are connected to the terminals.
Confirm that the ground wire has continuity to
ground.
²Check that fuse 13 (40 amp) in the integrated
power module (IPM) is OK. The fuse must be tight in
it's receptacle and all electrical connections must be
secure.
(3) When the above steps have been completed and
the rear glass heating grid is still inoperative, one or
more of the following is faulty. It may be necessary to
connect a DRBIIItscan tool to perform further diag-
nostics. Refer to Body Diagnostic Procedures.
²Rear window defogger switch in the A/C-heater
control.
²J1850 bus communication between the A/C-
heater control and the front control module (FCM).
²Rear window defogger (EBL) relay in the IPM.
²Rear window defogger (EBL) relay control circu-
ity in the IPM.
²Check for a loose wire connector or a wire
pushed out of a connector.
²Rear window grid lines (all grid lines would
have to be broken, or the power feed or ground wire
not connected, for the entire heating grid to be inop-
erative).
(4) If the system operation has been verified but
defogger switch LED indicator does not illuminate,
replace the A/C-heater control.
8G - 2 HEATED GLASSRS
HEATED GLASS (Continued)

Hard wired circuitry connects the heated seat sys-
tem components to each other through the electrical
system of the vehicle. These circuits may be con-
nected to each other, to the vehicle electrical system
and to the heated seat system components through
the use of a combination of soldered splices and
splice block connectors. Refer to the appropriate wir-
ing information for complete circuit schematic or con-
nector pin-out information.
OPERATION
The heated seat system components operate on
battery current received through a fuse in the Inte-
grated Power Module (IPM) on a fused ignition
switch output (run) circuit from the Body Control
Module (BCM). The system will only operate when
the ignition switch is in the On position. The heated
seat system will be turned Off automatically when-
ever the ignition switch is turned to any position
except On. Also, the heated seat system will not oper-
ate when the surface temperature of the seat cushion
cover at either heated seat sensor is above the
designed temperature set points of the system.
DIAGNOSIS AND TESTING
HEATED SEAT SYSTEM
The most efficient means of diagnosing the heated
seat system is by individual component. For diagno-
sis of a specific component refer to the following:
²Heated seat module, (Refer to 8 - ELECTRICAL/
ELECTRONIC CONTROL MODULES/MEMORY
HEATED SEAT/MIRROR MODULE - DIAGNOSIS
AND TESTING).
²Heated seat elements, (Refer to 8 - ELECTRI-
CAL/HEATED SEATS/HEATED SEAT ELEMENT -
DIAGNOSIS AND TESTING).
²Heated seat switch, (Refer to 8 - ELECTRICAL/
HEATED SEATS/DRIVER HEATED SEAT SWITCH
- DIAGNOSIS AND TESTING).
²Heated seat sensor, (Refer to 8 - ELECTRICAL/
HEATED SEATS/HEATED SEAT SENSOR - DIAG-
NOSIS AND TESTING).
Refer to the appropriate wiring information for
complete circuit schematic or connector pin-out infor-
mation.
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 hazard, rear window
wiper and washer switches. Each heated seat switch
provides a resistor multiplexed signal to its respec-
tive Heated Seat Module (HSM) through separate
hard wired circuits. Each switch has an Off, Low,
and High position so that both the driver and the
front seat passenger can select a preferred seat heat-
ing 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 SWITCH LOCATION
1 - HEATED SEAT SWITCHES
8G - 8 HEATED SEAT SYSTEMRS
HEATED SEAT SYSTEM (Continued)