Ground wires fuse panel fuse 23 JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual

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)

repaired and, if faulty or damaged, the entire a/c
heater control must be replaced. (Refer to 24 - HEAT-
ING & AIR CONDITIONING/CONTROLS/A/C
HEATER CONTROL - REMOVAL)
OPERATION
When the rear window defogger switch push but-
ton is depressed, it momentarily closes the rear win-
dow defogger switch sense circuit for the BCM to
ground. The BCM monitors the rear window defogger
switch sense circuit. Each time the BCM rear win-
dow defogger timer and logic circuitry sees another
input from the switch, it toggles a control output to
the rear window defogger relay. Energizing the rear
window defogger relay provides electrical current to
the rear window defogger grid and to the LED indi-
cator in the switch, which lights to indicate when the
defogger system is turned on. A dedicated fuse in the
junction block protects the rear window defogger
relay output circuit to the LED indicator.
DIAGNOSIS AND TESTING - REAR WINDOW
DEFOGGER SWITCH
For complete circuit diagrams, refer to the Appro-
priate Wiring Information.
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.
(1) Disconnect and isolate the battery negative
cable. Remove the a/c heater control from the instru-
ment panel and disconnect the 11-way (manual tem-
perature control) or 16-way (automatic zone control)
instrument panel wire harness connector from the a/c
heater control receptacle.
(2) Check for continuity between the ground cir-
cuit cavity of the 11-way or 16-way instrument panel
wire harness connector for the a/c heater control and
a good ground. There should be continuity. If OK, go
to Step 3. If not OK, repair the open ground circuit to
ground as required.
(3) Connect two jumper wires to the a/c heater
control 11-way or 16-way connector receptacle. Con-
nect one jumper from the ground circuit terminal inthe 11-way or 16-way a/c heater control connector
receptacle to a good ground. Connect the other
jumper from the fused rear window defogger relay
output circuit terminal of the 11-way or 16-way con-
nector receptacle to a 12-volt battery feed. The rear
window defogger switch LED indicator should light.
If OK, go to Step 4. If not OK, replace the faulty a/c
heater control.
(4) Check for continuity between the ground cir-
cuit and rear window defogger switch sense circuit
terminals of the 11-way or 16-way a/c heater control
connector receptacle. There should be momentary
continuity as the rear window defogger switch push
button is depressed, and then no continuity. If OK, go
to Step 5. If not OK, replace the faulty a/c heater
control.
(5) Disconnect the 22-way instrument panel wire
harness connector from the Body Control Module
(BCM) connector receptacle. Check for continuity
between the rear window defogger switch sense cir-
cuit cavity of the 11-way or 16-way instrument panel
wire harness connector for the a/c heater control and
a good ground. There should be no continuity. If OK,
go to Step 6. If not OK, repair the shorted rear win-
dow defogger switch sense circuit as required.
(6) Check for continuity between the rear window
defogger switch sense circuit cavities of the 11-way or
16-way instrument panel wire harness connector for
the a/c heater control and the 22-way instrument
panel wire harness connector for the BCM. There
should be continuity. If OK, refer to (Refer to 8 -
ELECTRICAL/HEATED GLASS/REAR WINDOW
DEFOGGER RELAY - DIAGNOSIS AND TESTING).
REMOVAL
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.
(Refer to 24 - HEATING & AIR CONDITIONING/
CONTROLS/A/C HEATER CONTROL - REMOVAL)
WJHEATED GLASS 8G - 7
REAR WINDOW DEFOGGER SWITCH (Continued)

DIAGNOSIS AND TESTING - SIDEVIEW
MIRROR
For complete circuit diagrams, refer to the appro-
priate wiring information. The wiring information
includes wiring diagrams, proper wire and connector
repair procedures, details of wire harness routing
and retention, connector pin-out information and
location views for the various wire harness connec-
tors, splices and grounds.
BOTH MIRRORS INOPERATIVE
(1) Check the operation of the power lock switch
on the driver side front door. If all of the doors lock
and unlock, replace the faulty Driver Door Module
(DDM). If not OK, go to Step 2.
(2) Check the operation of the power lock switch
on the passenger side front door. If all of the doors
lock and unlock, replace the faulty DDM. If not OK,
go to Step 3.
(3) Check the fused B(+) fuse in the Power Distri-
bution Center (PDC). If OK, go to Step 4. If not OK,
repair the shorted circuit or component as required
and replace the faulty fuse.
(4) Check for battery voltage at the fused B(+) fuse
in the PDC. If OK, go to Step 5. If not OK, repair the
open fused B(+) circuit to the battery as required.
(5) Disconnect and isolate the battery negative
cable. Remove the trim panel from the driver side
front door. Disconnect the 15-way door wire harness
connector from the DDM connector receptacle. Check
for continuity between the ground circuit cavity of
the 15-way door wire harness connector for the DDM
and a good ground. There should be continuity. If
OK, go to Step 6. If not OK, repair the open ground
circuit to ground as required.
(6)
Reconnect the battery negative cable. Check for
battery voltage at the fused B(+) circuit cavity of the
15-way door wire harness connector for the DDM. If
OK, replace the faulty DDM. If not OK, repair the open
fused B(+) circuit to the fuse in the PDC as required.
ONE MIRROR INOPERATIVE
(1) If the one inoperative mirror is on the passen-
ger side, go to Step 2. If the one inoperative mirror is
on the driver side, go to Step 3.
(2)
Check if the passenger front door will lock and
unlock using the power lock switch on the driver side
front door. If OK, go to Step 3. If not OK, go to Step 6.
(3) Disconnect and isolate the battery negative
cable. Remove the trim panel from the front door.
Disconnect the 12-way mirror wire harness connector
from the door wire harness connector.
(4) Using two jumper wires, test the mirror as
shown in the Mirror Test chart (Fig. 2). If the mirror
tests OK, go to Step 5. If the mirror does not test
OK, replace the faulty mirror.(5) Disconnect the 12-way door wire harness con-
nector from the door module connector receptacle.
Check all of the circuits of the door wire harness
between the connector for the mirror and the connec-
tor for the door module for opens or shorts. If all of
the circuits are OK, replace the faulty door module.
If any of the circuits are not OK, repair the open or
shorted circuit(s) as required.
(6) Use a DRB scan tool and the proper Diagnostic
Procedures manual to test and repair the faulty Pro-
grammable Communications Interface (PCI) data bus
communication between the two door modules.
NO MIRROR HEAT
If one or both mirror heaters are inoperative,
(Refer to 8 - ELECTRICAL/HEATED MIRRORS -
DESCRIPTION).
(1) Disconnect and isolate the battery negative
cable. Remove the front door trim panel on the side
of the inoperative mirror heater.
(2) Disconnect the 12-way door wire harness con-
nector from the door module connector receptacle.
Check for continuity between the heater switched
ground circuit cavity and the heater 12V supply cir-
cuit cavity of the 12-way door wire harness connector
Fig. 2 Mirror Test
POWER MIRROR TEST TABLE
APPLY 12
VOLTS TO:APPLY
GROUND TO:MIRROR
REACTION
DRIVER SIDE
1 7 LEFT
7 1 RIGHT
87UP
7 8 DOWN
PASSENGER SIDE
1 7 LEFT
7 1 RIGHT
87UP
7 8 DOWN
8N - 16 POWER MIRRORSWJ
SIDEVIEW MIRROR (Continued)