door control module JEEP GRAND CHEROKEE 2002 WJ / 2.G User Guide

Frequency (RF) Remote Keyless Entry (RKE)
receiver. The DDM and PDM control and integrate
many functions and features of the vehicle through
both hard wired outputs and messages over the PCI
data bus. The functions and features that the door
modules support or control include the following:
²Automatic Door Lock- The two door modules
provide an automatic door lock feature which locks
the doors when the vehicle is moving. This is a pro-
grammable feature.
²Automatic Door Unlock On Exit- The two
door modules provide an automatic door unlock on
exit feature. This feature will unlock all the doors if
they were locked via the automatic door lock feature
after the vehicle has stopped moving and the driver
door is opened. This is a programmable feature via
the EVIC.
²Customer Programmable Features- Each
door module provides support for certain customer
programmable features that are monitored on the
PCI bus.
²Cylinder Lock Switch Status- The DDM
monitors and transmits the status of the cylinder
lock switch on the driver side front door lock cylin-
der.
²Door Courtesy Lamp Control- Each door
module provides control of its own optional front
door-mounted courtesy lamp.
²Door Lock Inhibit- Each door module pro-
vides a door lock inhibit feature which prevents the
doors from being locked with a power lock switch ifthe key was left in the ignition and a front door is
open.
²Express-Down Window- The DDM provides
an express-down feature for the driver side front door
window only.
²Extended Window Operation- Both door
modules provide an extended power window opera-
tion feature that allows operation of the power win-
dows for 45 seconds following ignition Off or until a
front door is opened.
²Front Door Ajar Switch Status- Each door
module monitors and transmits the status of its own
front door ajar switch.
²Heated Mirrors- Each door module provides
control for its own optional heated outside rear view
mirror.
²Illuminated Entry- Each door module sup-
ports an illuminated entry feature through its own
optional front door-mounted courtesy lamp.
²Memory Mirrors- Each door module provides
control for its own optional memory outside rear view
mirror.
²Memory Switch- The DDM monitors the sta-
tus of the optional memory switch and controls the
illumination of the memory switch ªsetº Light Emit-
ting Diode (LED) indicator and illumination lamps.
²Memory System- The DDM transmits memory
set and recall messages based upon inputs from the
memory switch. If the optional RKE linked to mem-
ory feature is enabled, the DDM will also transmit
memory recall messages based upon memory
requests received from the Remote Keyless Entry
(RKE) system in the PDM. Certain memory system
features are programmable.
²Power Foldaway Mirrors - Export Only-
Each door module provides support for the optional
power foldaway outside mirrors. The DDM also
houses the control switch for this system.
²Power Lock Control- The DDM provides con-
trol for the driver side front door power lock motor,
while the PDM provides control for the power lock
motors of the three remaining doors and the liftgate.
²Power Lock Switch Status- Each door mod-
ule monitors and transmits the status of its own inte-
gral power lock switch.
²Power Window Control- Each door module
provides control for both the front and rear door
power window motors and the rear door power win-
dow switches on the same side of the vehicle.
²Power Window Switch Status- The DDM
monitors and transmits the status of its integral pas-
senger side front and rear power window switches.
²Remote Keyless Entry- The PDM monitors
and transmits the status of the Remote Keyless
Entry (RKE) system and provides support for the
RKE Lock (with the optional horn chirp and park
Fig. 7 Door Module
1 - FRONT DOOR TRIM PANEL
2 - SCREW (5)
3 - DOOR MODULE
8E - 8 ELECTRONIC CONTROL MODULESWJ
DOOR MODULE (Continued)

lamp flash features), Unlock with the optional RKE
unlock, and Panic Mode functions. The optional RKE
features are programmable.
²Switch Illumination- Each door module pro-
vides control of the power window and power lock
switch illumination for the front and rear doors on
the same side of the vehicle. The DDM provides con-
trol of the power mirror switch illumination.
²Window Lockout- The DDM monitors and
transmits the status of its integral window lockout
switch to provide the power window lockout feature
and coordinate power window switch knob illumina-
tion.
The door modules are serviced only as complete
units. Many of the features in the vehicle controlled
or supported by the door modules are programmable
using either the Electronic Vehicle Information Cen-
ter (EVIC) user interface, or the DRBIIItscan tool. If
a door module is damaged or faulty, the entire door
module unit must be replaced.
OPERATION
The microprocessor-based DDM and PDM hard-
ware and software monitors integral and hard wired
external switch inputs as well as those resources it
shares with other electronic modules in the vehicle
through its communication over the PCI data bus
network. The internal programming and all of these
inputs allow the DDM or PDM microprocessor to
determine the tasks it needs to perform and their
priorities, as well as both the standard and optional
features that it should provide.
The DDM and PDM are powered by a fused bat-
tery circuit so that they can operate regardless of the
ignition switch position. The DDM and PDM cir-
cuitry is grounded to the chassis beneath the front
seat.
The DDM and PDM can be diagnosed using a
DRBIIItscan tool. Refer to the appropriate diagnos-
tic information.
HARD WIRED INPUTS
The hard wired inputs to the door modules include
the following:
²Door ajar switch sense
²Driver door key cylinder switch sense (DDM)
²Fused B(+)
²Ground
²Memory switch mux (DDM)
²Mirror horizontal position signal
²Mirror vertical position signal
²PCI bus
HARD WIRED OUTPUTS
The hard wired outputs of the door modules
include the following:
²Courtesy lamp driver
²Courtesy lamp ground
²Diagnostic out (DDM)
²Door/liftgate lock driver
²Door/liftgate unlock driver
²Door switch illumination (rear power window)
²Front window driver (down)
²Front window driver (up)
²Memory set indicator driver (DDM)
²Memory switch return (DDM)
²Mirror common driver
²Mirror heater ground
²Mirror heater 12V supply
²Rear window driver (down)
²Rear window driver (up)
²Mirror horizontal driver
²Mirror sensor ground
²Mirror vertical driver
²PCI bus
²Switch illumination driver (memory - DDM)
MESSAGING
The door modules use the following messages
received from other electronic modules over the PCI
data bus:
²Accessory Delay Control (PDM)
²Courtesy Lamp Status (BCM)
²Door Ajar Status/Rear Doors (BCM)
²Door Lock Status (DDM/PDM)
²Ignition Switch Position (BCM)
²Key-In Ignition Status (BCM)
²Programmable Features Preferences/Auto Lock/
Auto Unlock/RKE Unlock Sequence/RKE Link to
Memory (EVIC)
²Memory Recall (DDM)
²Rear Window Defogger Relay Status (BCM)
²Vehicle Speed (PCM)
The door modules provide the following messages
to other electronic modules over the PCI data bus:
²Cylinder Lock Switch Status (BCM)
²Door Ajar Status/Front Doors (BCM/DDM/PDM)
²Door Lock Status (DDM/PDM)
²Memory Recall (PDM/MHSM/MSM/Radio)
²Memory Set Switch Status (PDM/MHSM/MSM/
Radio)
²Panic Control (BCM)
²Power Window Switch Status (PDM)
²RKE Status (BCM/DDM)
²Window Lockout Switch Status (PDM)
WJELECTRONIC CONTROL MODULES 8E - 9
DOOR MODULE (Continued)

DIAGNOSIS AND TESTING - DOOR MODULE
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.
The hard wired inputs to and outputs from the
Driver Door Module (DDM) or the Passenger Door
Module (PDM) may be diagnosed and tested using
conventional diagnostic tools and procedures. It is
suggested that the proper operation of the inopera-
tive power window motor, power door lock motor,
power liftgate lock motor, power mirror motors, or
heated mirror grid be confirmed using jumper wires
to bypass the door module. If the inoperative compo-
nent operates when the door module is bypassed,
check the circuits between the component and the
door module, as well as the fused B(+) and ground
circuits of the door module for shorts or opens.
These conventional diagnostic methods may not
prove conclusive in the diagnosis of the DDM or the
PDM. In order to obtain conclusive testing of these
modules, the Programmable Communications Inter-
face (PCI) data bus network and all of the modules
that provide inputs to or receive outputs from the
door modules must also be checked. The most reli-
able, efficient, and accurate means to diagnose the
DDM, the PDM, the PCI data bus network, and the
modules that provide inputs to or receive outputs
from the door modules requires the use of a DRBIIIt
scan tool and the appropriate diagnostic information.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the trim panel from the front door.
(Refer to 23 - BODY/DOOR - FRONT/TRIM PANEL -
REMOVAL).
(3) Remove the door module from the back of the
front door trim panel (Fig. 8).
(4) Remove the door module from the front door
trim panel.
INSTALLATION
(1) Position the door module onto the front door
trim panel.
(2) Install the door module to the back of the front
door trim panel (Fig. 8). Tighten the screws to 2.2
N´m (20 in. lbs.).
(3) Reinstall the trim panel onto the front door.
(Refer to 23 - BODY/DOOR - FRONT/TRIM PANEL -
INSTALLATION).
(4) Reconnect the battery negative cable.
MEMORY HEATED SEAT/
MIRROR MODULE
DESCRIPTION
There are two different modules that can be used
in the optional heated seat system. The Heated Seat
Module (HSM) is used on vehicles that are not
equipped with the optional Memory System. The
Memory Heated Seat Module (MHSM) is used on
vehicles that are equipped with the optional Memory
System and the optional heated seat system.Refer to
Memory Systemin Power Seat Systems for more
information on the memory system option.
The module is mounted on a bracket that is located
between the power seat track and the seat cushion
frame (Fig. 9). The HSM or MHSM is used to control
the heated seat system functions for both front seats.
The HSM or MHSM contains a central processing
unit that communicates with other modules on the
Fig. 8 Door Module Remove/Install
1 - FRONT DOOR TRIM PANEL
2 - SCREW (5)
3 - DOOR MODULE
8E - 10 ELECTRONIC CONTROL MODULESWJ
DOOR MODULE (Continued)

Programmable Communications Interface (PCI) data
bus network.
For diagnosis of the HSM, MHSM or the PCI data
bus, a DRBIIItscan tool and the proper Diagnostic
Procedures manual are recommended. The HSM or
MHSM cannot be repaired and, if faulty or damaged,
it must be replaced.
OPERATION
The MSM receives hard wired inputs from the
power seat switch and the potentiometers on each of
the driver side power seat motors. The MSM receives
messages over the PCI data bus from the Driver
Door Module (DDM) (memory switch status), the
Powertrain Control Module (PCM) (vehicle speed sta-
tus), and the Body Control Module (seat belt switch
status).The MSM will prevent the seat memory recall
function from being initiated if the driver side seat
belt is buckled, if the transmission gear selector lever
is not in the Park or Neutral positions, or if the vehi-
cle is moving.
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - HEATED SEAT
MODULE
Visually inspect the related wiring harness connec-
tors. Look for broken, bent, pushed out, or corroded
terminals. If any of the above conditions are present,
repair as necessary. If not, use a DRBIIItscan tool
and the proper Diagnostic Procedures Manual to test
the HSM or MHSM. For complete circuit diagrams,
refer toPower Seat Premium I/IIIin Wiring Dia-
grams.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the driver side front bucket seat from
the power seat track unit. Refer toBucket Seat
Track Adjusterin Body for the procedure.
(3) Lift the heated seat module off of the power
seat track and disconnect the power seat wire har-
ness connectors (Fig. 10).
(4) Remove the module from the bracket.
Fig. 9 Heated Seat Module Remove/Install
1 - NUT (4)
2 - SEAT CUSHION FRAME
3 - POWER SEAT TRACK
4 - STUD (4)
5 - MODULE
6 - BRACKET
Fig. 10 Heated Seat Module Remove/Install
1 - NUT (4)
2 - SEAT CUSHION FRAME
3 - POWER SEAT TRACK
4 - STUD (4)
5 - MODULE
6 - BRACKET
WJELECTRONIC CONTROL MODULES 8E - 11
MEMORY HEATED SEAT/MIRROR MODULE (Continued)

STANDARD PROCEDURE - IGNITION-OFF
DRAW TEST
The term Ignition-Off Draw (IOD) identifies a nor-
mal condition where power is being drained from the
battery with the ignition switch in the Off position. A
normal vehicle electrical system will draw from five
to thirty-five milliamperes (0.005 to 0.035 ampere)
with the ignition switch in the Off position, and all
non-ignition controlled circuits in proper working
order. Up to thirty-five milliamperes are needed to
enable the memory functions for the Powertrain Con-
trol Module (PCM), digital clock, electronically tuned
radio, and other modules which may vary with the
vehicle equipment.
A vehicle that has not been operated for approxi-
mately twenty days, may discharge the battery to an
inadequate level. When a vehicle will not be used for
twenty days or more (stored), remove the IOD fuse
from the Power Distribution Center (PDC). This will
reduce battery discharging.Excessive IOD can be caused by:
²Electrical items left on.
²Faulty or improperly adjusted switches.
²Faulty or shorted electronic modules and compo-
nents.
²An internally shorted generator.
²Intermittent shorts in the wiring.
If the IOD is over thirty-five milliamperes, the
problem must be found and corrected before replac-
ing a battery. In most cases, the battery can be
charged and returned to service after the excessive
IOD condition has been corrected.
(1) Verify that all electrical accessories are off.
Turn off all lamps, remove the ignition key, and close
all doors. If the vehicle is equipped with an illumi-
nated entry system or an electronically tuned radio,
allow the electronic timer function of these systems
to automatically shut off (time out). This may take
up to three minutes. See the Electronic Module Igni-
tion-Off Draw Table for more information.
ELECTRONIC MODULE IGNITION-OFF DRAW (IOD) TABLE
ModuleTime Out?
(If Yes, Interval And Wake-Up Input)IODIOD After Time
Out
Radio No1to3
milliamperesN/A
Audio Power
AmplifierNoup to 1
milliampereN/A
Body Control Module
(BCM)No5.90
milliamperes
(max.)N/A
Powertrain Control
Module (PCM)No 0.95 milliampere N/A
Transmission Control
Module (TCM) 4.7L
w/45RFEYES (20 minutes, ignition on) 130 milliamperes 0.64 milliampere
ElectroMechanical
Instrument Cluster
(EMIC)No 0.44 milliampere N/A
Combination Flasher No 0.08 milliampere N/A
(2) Determine that the underhood lamp is operat-
ing properly, then disconnect the lamp wire harness
connector or remove the lamp bulb.
(3) Disconnect the battery negative cable.
(4) Set an electronic digital multi-meter to its
highest amperage scale. Connect the multi-meter
between the disconnected battery negative cable ter-
minal clamp and the battery negative terminal post.
Make sure that the doors remain closed so that the
illuminated entry system is not activated. The multi-
meter amperage reading may remain high for up tothree minutes, or may not give any reading at all
while set in the highest amperage scale, depending
upon the electrical equipment in the vehicle. The
multi-meter leads must be securely clamped to the
battery negative cable terminal clamp and the bat-
tery negative terminal post. If continuity between the
battery negative terminal post and the negative cable
terminal clamp is lost during any part of the IOD
test, the electronic timer function will be activated
and all of the tests will have to be repeated.
WJBATTERY SYSTEM 8F - 13
BATTERY (Continued)

HEATED SYSTEMS
TABLE OF CONTENTS
page page
HEATED GLASS........................... 1
HEATED MIRRORS......................... 8HEATED SEAT SYSTEM..................... 9
HEATED GLASS
TABLE OF CONTENTS
page page
HEATED GLASS
DESCRIPTION - REAR WINDOW DEFOGGER . . 1
OPERATION - REAR WINDOW DEFOGGER....2
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SYSTEM...................2
REAR WINDOW DEFOGGER GRID
DESCRIPTION..........................3
OPERATION............................3
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER GRID......................3
STANDARD PROCEDURE - REAR GLASS
HEATING GRID REPAIR.................4
REAR WINDOW DEFOGGER RELAY
DESCRIPTION..........................5OPERATION............................5
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER RELAY.....................5
REMOVAL.............................6
INSTALLATION..........................6
REAR WINDOW DEFOGGER SWITCH
DESCRIPTION..........................6
OPERATION............................7
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SWITCH...................7
REMOVAL.............................7
HEATED GLASS
DESCRIPTION - REAR WINDOW DEFOGGER
An electrically heated rear window defogger is
standard factory-installed equipment on this model.
Electrically heated outside rear view mirrors are
available factory-installed optional equipment. When
the rear window defogger system is turned on, elec-
tric heater grids on the liftgate flip-up glass and
behind both outside rear view mirror glasses are
energized. These electric heater grids produce heat to
help clear the rear window glass and the outside rear
view mirrors of ice, snow, or fog. The rear window
defogger system control circuit uses ignition switched
battery current, so the system will only operate when
the ignition switch is in the On position.
This group covers the following components of the
rear window defogger system:
²Rear glass heating grid
²Rear window defogger relay²Rear window defogger switch.
Certain functions and features of the rear window
defogger system rely upon resources shared with
other electronic modules in the vehicle over the Pro-
grammable Communications Interface (PCI) data bus
network. The PCI data bus network allows the shar-
ing of sensor information. 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 fea-
ture capabilities. For diagnosis of these electronic
modules or of the PCI data bus network, use a
DRBIIItscan tool and (Refer to Appropriate Diagnos-
tic Information).
The other electronic modules that may affect
proper system operation are:
²Body Control Module (BCM)- Refer to Elec-
tronic Control Modules for more information.
²Driver Door Module (DDM)- Refer to Elec-
tronic Control Modules for more information.
WJHEATED SYSTEMS 8G - 1

²Passenger Door Module (PDM)- Refer to
Electronic Control Modules for more information.
OPERATION - REAR WINDOW DEFOGGER
The rear window defogger system is controlled by a
momentary switch that is integral to the a/c heater
control located in the center stack area of the instru-
ment panel. A Light-Emitting Diode (LED) in the
switch button will light to indicate when the rear
window defogger system is turned on. The BCM,
which contains the rear window defogger system
timer and control logic, monitors the status of the
defogger switch through a hard-wired input. The
BCM then sends control outputs through a hard
wired circuit to energize or de-energize the defogger
relay.
The electrically heated outside rear view mirror
heating grids are also controlled by the rear window
defogger switch. When the BCM receives an input
from the switch, it sends a defogger switch status
message to the DDM and the PDM over the PCI data
bus. The DDM and PDM respond to the defogger
switch status messages by energizing or de-energiz-
ing the battery current feed to their respective out-
side rear view mirror heating grids.
The rear window defogger system will be automat-
ically turned off after a programmed time interval of
about ten minutes. 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 defogger 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 rear win-
dow defogger switch again.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the rear window defogger system.
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SYSTEM
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 AN ACCIDENTAL
AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.For complete circuit diagrams, (Refer to Appropri-
ate Wiring Information). The operation of the electri-
cally heated rear window defogger system can be
confirmed in one of the following manners:
1. Turn the ignition switch to the On position.
While monitoring the instrument panel voltmeter,
depress the rear window defogger switch to the On
position. When the rear window defogger switch is
turned On, a distinct voltmeter needle deflection
should be noted.
2. Turn the ignition switch to the On position.
Depress the rear window defogger switch to the On
position. The rear window defogger operation can be
checked by feeling the rear window or outside rear
view mirror glass. A distinct difference in tempera-
ture between the grid lines and the adjacent clear
glass or the mirror glass can be detected within three
to four minutes of operation.
3. Using a 12-volt DC voltmeter, contact the rear
glass heating grid terminal A (right side) with the
negative lead, and terminal B (left side) with the pos-
itive lead (Fig. 1). The voltmeter should read battery
voltage.
The above checks will confirm rear window defog-
ger system operation. Illumination of the rear win-
dow defogger switch LED indicator means that there
is battery current available at the output of the rear
window defogger relay, but does not confirm that bat-
tery current is reaching the rear glass heating grid
lines.
If the rear window defogger system does not oper-
ate, the problem should be isolated in the following
manner:
Fig. 1 REAR WINDOW GLASS GRID TEST
1 - TERMINAL ªAº
2 - TERMINAL ªBº
3 - FEED WIRE
4 - MID-POINT ªCº (TYPICAL)
5 - HEATED REAR WINDOW DEFOGGER GRID
6 - GROUND WIRE
8G - 2 HEATED GLASSWJ
HEATED GLASS (Continued)

(1) Confirm that the ignition switch is in the On
position.
(2) Ensure that the rear glass heating grid feed
and ground terminals are connected to the glass.
Confirm that the ground wire has continuity to
ground.
(3) Check the fused B(+) fuse in the Power Distri-
bution Center (PDC). The fuse must be tight in its
receptacles and all electrical connections must be
secure.
When the above steps have been completed and the
rear glass heating grid is still inoperative, one or
more of the following is faulty:
²Rear window defogger switch
²Rear window defogger relay
²Body Control Module (BCM)
²Rear window grid lines (all grid lines would
have to be broken or one of the feed wires discon-
nected for the entire system to be inoperative).
When the above steps have been completed and the
heated mirror glass heating grid is still inoperative,
one or more of the following is faulty:
²Body Control Module (BCM)
²Programmable Communications Interface (PCI)
data bus
²Driver Door Module (DDM) or Passenger Door
Module (PDM)
²Outside rear view mirror heating grids.
If turning the rear window defogger system on pro-
duces a severe voltmeter deflection, check for a short
circuit between the rear window defogger relay out-
put and the rear glass heating grid.
REAR WINDOW DEFOGGER
GRID
DESCRIPTION
The electrically heated rear window glass is stan-
dard equipment on this model. The liftgate flip-up
glass has two electrically conductive vertical bus bars
and a series of horizontal grid lines made of a silver-
ceramic material, which is baked on and bonded to
the inside surface of the glass. These grid lines and
the bus bars comprise a parallel electrical circuit. A
spade type terminal near the top of each bus bar
accept the connectors from the two coiled liftgate
wire harness take outs.
The grid lines and bus bars are highly resistant to
abrasion. However, it is possible for an open circuit
to occur in an individual grid line, resulting in no
current flow through the line. The grid lines can be
damaged or scraped off with sharp instruments. Care
should be taken when cleaning the glass or removing
foreign materials, decals, or stickers from the glass.Normal glass cleaning solvents or hot water used
with rags or toweling is recommended.
A repair kit is available to repair the grid lines and
bus bars, or to reinstall the heated glass terminals.
(Refer to 8 - ELECTRICAL/HEATED GLASS/REAR
WINDOW DEFOGGER GRID - STANDARD PROCE-
DURE)
OPERATION
The rear glass heating grid is energized and de-en-
ergized by the rear window defogger relay. The Body
Control Module (BCM) monitors the rear window
defogger switch. When the BCM receives an input
from the switch, it energizes or de-energizes the rear
window defogger relay through a hard wired control
output. The rear defogger relay switches fused bat-
tery current to the rear window grid lines through
the bus bars. The grid lines heat the rear window
glass to clear the surface of ice, snow or fog. Protec-
tion for the rear glass heating grid circuit is provided
by a fuse in the Power Distribution Center (PDC).
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER GRID
For complete circuit diagrams, (Refer to Appropri-
ate Wiring Information). To detect breaks in the rear
glass heating grid lines, the following procedure is
required:
(1) Turn the ignition switch to the On position.
Turn the rear window defogger system on. The rear
window defogger switch LED indicator should light.
If OK, go to Step 2. If not OK, (Refer to 8 - ELEC-
TRICAL/HEATED GLASS/REAR WINDOW DEFOG-
GER RELAY - DIAGNOSIS AND TESTING).
(2) Using a 12-volt DC voltmeter, contact the rear
glass heating grid vertical bus bar on the right side
of the vehicle with the negative lead. With the posi-
tive lead, contact the rear glass heating grid vertical
bus bar on the left side of the vehicle. The voltmeter
should read battery voltage. If OK, go to Step 3. If
not OK, repair the open rear window defogger relay
output circuit to the rear window defogger relay as
required.
(3) With the positive voltmeter lead still contacting
the rear glass heating grid vertical bus bar on the
left side of the vehicle, move the negative lead of the
voltmeter to a good body ground point. The voltage
reading should not change. If OK, go to Step 4. If not
OK, repair the ground circuit to ground as required.
(4) Connect the negative lead of the voltmeter to
the right side bus bar and touch each grid line at
midpoint C with the positive lead (Fig. 2). A reading
of approximately six volts indicates a line is good. A
reading of zero volts indicates a break in the grid
line between midpoint C and the left side rear glass
heating grid bus bar. A reading of ten to fourteen
WJHEATED GLASS 8G - 3
HEATED GLASS (Continued)

nector for the multi-function switch. There should be
continuity. If OK, go to Step 11. If not OK, repair the
open hazard switch sense circuit between the multi-
function switch and the combination flasher.
(11) Check for continuity between the turn switch
sense circuit of the instrument panel wire harness
connector for the multi-function switch and a good
ground. There should be no continuity. If OK, go to
Step 12. If not OK, repair the shorted left turn
switch sense circuit between the multi-function
switch and the combination flasher.
(12) Check for continuity between the left turn
switch sense circuit of the JB for the combination
flasher and the instrument panel wire harness con-
nector for the multi-function switch. There should be
continuity. If OK, go to Step 13. If not OK, repair the
open left turn switch sense circuit between the multi-
function switch and the combination flasher.
(13) Check for continuity between the right turn
switch sense circuit of the instrument panel wire
harness connector for the left multi-function switch
and a good ground. There should be no continuity. If
OK, go to Step 14. If not OK, repair the shorted right
turn switch sense circuit between the left multi-func-
tion switch and the combination flasher.
(14) Check for continuity between the right turn
switch sense circuit of the JB for the combination
flasher and the instrument panel wire harness con-
nector for the multi-function switch. There should be
continuity. If OK, test the left multi-function switch.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/LEFT MULTI-FUNCTION SWITCH -
DIAGNOSIS AND TESTING). If not OK, repair the
open right turn switch sense circuit between the
multi-function switch and the combination flasher as
required.
SPECIFICATIONS
EXTERIOR LAMPS
CAUTION: Do not use bulbs other than the bulbs
listed in the Bulb Application Table. Damage to
lamp can result. Do not touch halogen bulbs with
fingers or other oily surfaces. Bulb life will be
reduced.
LAMP BULB TYPE
BACK-UP 3157
CENTER HIGH
MOUNTED STOP LAMP921
FOG LAMP 9005
FRONT SIDE MARKER 194/194NA
LAMP BULB TYPE
FRONT TURN SIGNAL 3157/3157NA
HIGH BEAM 9005XS
LOW BEAM 9006XS
LICENSE PLATE 168
TAIL/BRAKE 3157
REAR TURN SIGNAL 3157
UNDERHOOD LAMP 561
AUTO HEADLAMP SENSOR
DIAGNOSIS AND TESTING - AUTO HEADLAMP
SENSOR (AHL)
The auto headlamp sensor needs real sunlight to
properly register the light level. When auto head-
lamps are enabled indoors, the headlamps may be
turned on. The sensor is located in the center of the
defroster grille at the base of the windshield. There
are no faults set in the Body Control Module (BCM)
for a inoperative or missing AHL Sensor. Symptom of
a missing sensor or unconnected sensor would be
that the Headlamps and Parklamps turn on when
the vehicle is started and there is a high level of
ambient light present (ie. daytime). Auto headlamps
should not function in the presence of daylight.
REMOVAL
(1) Remove the instrument panel top cover. (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - REMOVAL) for service proce-
dures.
(2) Remove the screw attaching auto headlamp
sensor to instrument panel (Fig. 1).
(3) Disengage the harness connector from auto
headlamp sensor.
(4) Separate the auto headlamp sensor from
instrument panel.
INSTALLATION
(1) Position the auto headlamp sensor on instru-
ment panel.
(2) Engage the harness connector to auto head-
lamp sensor.
(3) Install the screw attaching auto headlamp sen-
sor to instrument panel.
(4) Install the instrument panel top cover. (Refer
to 23 - BODY/INSTRUMENT PANEL/INSTRUMENT
PANEL TOP COVER - INSTALLATION) for service
procedures.
8L - 4 LAMPS/LIGHTING - EXTERIORWJ
LAMPS/LIGHTING - EXTERIOR (Continued)

INSTALLATION - BULB
CAUTION: Do not touch the bulb glass with fingers
or other oily surfaces. Reduced bulb life will result.
(1) Position the bulb into socket and push into
place.
(2) Position the bulb socket in headlamp and turn
the bulb socket one quarter turn clockwise.
(3) Install the headlamp.
HEADLAMP SWITCH
DESCRIPTION
The headlamp switch is part of the left multi-func-
tion switch. A knob on the end of the multi-function
switch control stalk controls all of the exterior light-
ing switch functions. The exterior lighting switch is
hard wired to the Body Control Module (BCM).
The exterior lighting switch cannot be adjusted or
repaired and, if faulty or damaged, the entire left
multi-function switch unit must be replaced. (Refer
to 8 - ELECTRICAL/LAMPS/LIGHTING - EXTERI-
OR/TURN SIGNAL/HAZARD SWITCH - REMOVAL)
for the service procedures. (Refer to 8 - ELECTRI-
CAL/ELECTRONIC CONTROL MODULES/BODY
CONTROL/CENTRAL TIMER MODUL - DESCRIP-
TION) for more information on this component.
OPERATION
The exterior lighting switch uses a hard wired five
volt reference circuit from the BCM, resistor multi-
plexing and a hard wired switch output circuit to
provide the BCM with a zero to five volt signal thatindicates the status of all of the exterior lighting
switch settings. The BCM then uses control outputs
to energize the headlamp and park lamp relays that
activate the exterior lighting circuits.
The BCM monitors the exterior lighting switch sta-
tus, then sends the proper switch status messages to
other modules over the Programmable Communica-
tions Interface (PCI) data bus network. The exterior
lighting switch status is also used by the BCM as an
input for chime warning system operation.
DIAGNOSIS AND TESTING Ð HEADLAMP
SWITCH
Before testing the headlamp switch, turn on the
exterior lighting and open the driver side front door.
If the exterior lamps of the vehicle operate, but there
is no chime warning issued with the driver side front
door open, (Refer to 8 - ELECTRICAL/LAMPS/
LIGHTING - INTERIOR/DOOR AJAR SWITCH -
DIAGNOSIS AND TESTING). If the exterior lamps
of the vehicle are inoperative, but the chime warning
is issued, (Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING - EXTERIOR - DIAGNOSIS AND TESTING).
If the exterior lamps and the chime warning are
both inoperative, test the left multi-function switch.
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR - DIAGNOSIS AND TESTING). If the
multi-function switch tests OK, proceed as follows.
The following tests will help to locate a short or open
in the hard wired circuits between the multi-function
switch and the Body Control Module (BCM). For
complete circuit diagrams, refer to the appropriate
wiring information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO ELECTRICAL, RESTRAINTS
BEFORE ATTEMPTING ANY 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.
(1) Disconnect and isolate the battery negative
cable. Disconnect the instrument panel wire harness
connector from the left multi-function switch connec-
tor. Disconnect the instrument panel wire harness
connector from the Body Control Module (BCM).
Check for continuity between the headlamp switch
mux circuit of the instrument panel wire harness
connector for the multi-function switch and a good
ground. There should be no continuity. If OK, go to
Step 2. If not OK, repair the shorted headlamp
switch mux circuit.
(2) Check for continuity between the headlamp
switch mux circuit of the instrument panel wire har-
Fig. 13 Headlamp Bulb
1 - HIGH BEAM BULB
2 - LOW BEAM BULB
3 - MARKER BULB
4 - PARK/TURN SIGNAL BULB
WJLAMPS/LIGHTING - EXTERIOR 8L - 15
HEADLAMP (Continued)