2002 JEEP GRAND CHEROKEE Workshop Manual

parking sensors automatic transmission fluid brake rotor spark plugs light USB port

Page 513 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual 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

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)

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JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual for the door module. There should be continuity. If
OK, use a DRB scan tool and the proper Diagnostic
Procedures manual to test the door module and the
PCI data bus. If not OK, replace the faulty powe

Page 515 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual POWER SEAT SYSTEM
TABLE OF CONTENTS
page page
POWER SEAT SYSTEM
DESCRIPTION
DESCRIPTION........................18
DESCRIPTION - MEMORY SYSTEM.......19
OPERATION
OPERATION - POWER SEAT SYSTEM.....20
OP

POWER SEAT SYSTEM
TABLE OF CONTENTS
page page
POWER SEAT SYSTEM
DESCRIPTION
DESCRIPTION........................18
DESCRIPTION - MEMORY SYSTEM.......19
OPERATION
OPERATION - POWER SEAT SYSTEM.....20
OPERATION - MEMORY SYSTEM.........20
DIAGNOSIS AND TESTING
DIAGNOSIS & TESTING - POWER SEAT
SYSTEM............................20
DIAGNOSIS & TESTING - MEMORY
SYSTEM............................20
DRIVER SEAT SWITCH
DESCRIPTION.........................21
OPERATION...........................21
DIAGNOSIS AND TESTING - DRIVER SEAT
SWITCH............................22
REMOVAL.............................23
INSTALLATION.........................23
LUMBAR CONTROL SWITCH
DESCRIPTION.........................24
OPERATION...........................24
DIAGNOSIS AND TESTING - POWER LUMBAR
SWITCH............................24
REMOVAL.............................24
INSTALLATION.........................25
LUMBAR MOTOR
DESCRIPTION.........................25OPERATION...........................26
DIAGNOSIS AND TESTING - POWER LUMBAR
ADJUSTER..........................26
MEMORY SET SWITCH
DESCRIPTION.........................26
OPERATION...........................26
DIAGNOSIS AND TESTING - MEMORY
SWITCH............................27
REMOVAL.............................27
INSTALLATION.........................27
PASSENGER SEAT SWITCH
DESCRIPTION.........................27
OPERATION...........................28
DIAGNOSIS AND TESTING - PASSENGER
SEAT SWITCH........................28
REMOVAL.............................29
INSTALLATION.........................29
RECLINER MOTOR
DESCRIPTION.........................30
OPERATION...........................30
DIAGNOSIS AND TESTING - RECLINER
MOTOR .............................30
POWER SEAT TRACK
DESCRIPTION.........................31
OPERATION...........................32
DIAGNOSIS AND TESTING - POWER SEAT
TRACK.............................32
POWER SEAT SYSTEM
DESCRIPTION
DESCRIPTION
Driver and passenger power front seats are an
available factory-installed option for this vehicle. The
power seat system option allows the driver and front
seat passenger to electrically adjust their seating
positions for optimum control and comfort using the
power seat switches located on the outboard seat
cushion side shield of each front seat. The power seat
system receives battery current through a fuse in the
Power Distribution Center (PDC) and a circuit
breaker in the junction block so that the power seats
remain operational, regardless of the ignition switch
position.Four power seat options are offered on this vehicle,
depending upon the model. They are as follows:
²Six-way power drivers seat with manual
passenger seat- This power seat package is an
option on Laredo models equipped with cloth-
trimmed seats and includes a six-way adjustable
driver seat track with manual seat back recliners.
²Six-way power driver and passenger seat-
This power seat package is an option on Laredo mod-
els equipped with cloth or leather-trimmed seats and
includes six-way adjustable seat tracks with manual
seat back recliners. Heated Seats are available on
leather-trimmed seats.
²Ten-way power drivers seat with Memory
and Six-way power passenger seat- This power
seat package is standard on Limited models. This
option includes a six-way adjustable seat track with
power seat back recliners and power lumbar supports
for the driver and six-way only for the passenger.
8N - 18 POWER SEAT SYSTEMWJ

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JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual ²Ten-way power drivers and passenger seats
with Memory- This power seat option is standard
on Overland models and optional on Limited models.
This option includes a six-way adjustable seat cush-
ion

²Ten-way power drivers and passenger seats
with Memory- This power seat option is standard
on Overland models and optional on Limited models.
This option includes a six-way adjustable seat cush-
ion track with power seat back recliners and power
lumbar supports. Heated Seats are standard with
this option.
Refer toHeated Seat Systemfor more informa-
tion on the heated seat option. Refer toMemory
Systemin the Memory System section of this group
for more information on the memory system.
The power seat system includes the following com-
ponents:
²Power lumbar adjuster (ten-way power seat
only)
²Power lumbar switch (ten-way power seat only)
²Power seat recliner (ten-way power seat only)
²Power seat switch
²Power seat track.
Refer toPower Seatin Wiring Diagrams for com-
plete circuit diagrams. Following are general descrip-
tions of the major components in the power seat/
memory seat system.
DESCRIPTION - MEMORY SYSTEM
An electronic memory system is standard equip-
ment on the Limited model. The memory system is
able to store and recall the driver side power seat
positions (including the power recliner position), and
both outside power mirror positions for two drivers.
For vehicles with a radio connected to the Program-
mable Communications Interface (PCI) data bus net-
work, the memory system is also able to store and
recall up to twenty - ten AM and ten FM - radio sta-
tion presets for two drivers. The memory system also
will store and recall the last station listened to for
each driver, even if it is not one of the twenty preset
stations.
The memory system will automatically return to
all of these settings when the corresponding num-
bered and color-coded button (Driver 1 - Black, or
Driver 2 - Gray) of the memory switch on the driver
side front door trim panel is depressed, or when the
doors are unlocked using the corresponding num-
bered and color-coded (Driver 1 - Black, or Driver 2 -
Gray) Remote Keyless Entry (RKE) transmitter. A
customer programmable feature of the memory sys-
tem allows the RKE recall of memory features to be
disabled in cases where there are more than two
drivers of the vehicle.
The memory system also has a customer program-
mable easy exit feature that will move the driver
seat rearward 55 millimeters (two inches) or to the
end of its travel, whichever occurs first, when the key
is removed from the ignition switch lock cylinder.A Memory Seat Module (MSM) or Memory Heated
Seat Module (MHSM) are used on this model to con-
trol and integrate the many electronic functions and
features included in the memory system. On vehicles
equipped with the heated seat system option, the
MHSM also controls the functions and features of
that system.
The memory system includes the following compo-
nents:
²Memory seat module (or memory heated seat
module)
²Memory switch
²Position potentiometers on both outside power
mirrors
²Position potentiometers on the driver side power
seat track and power seat recliner motors.
²Radio receiver (if PCI data bus capable).
Certain functions and features of the memory sys-
tem rely upon resources shared with other electronic
modules in the vehicle over the Programmable Com-
munications Interface (PCI) data bus network. The
PCI data bus network allows the sharing of sensor
information. This helps to reduce wire harness com-
plexity, 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 capabil-
ities. For diagnosis of these electronic modules or of
the PCI data bus network, the use of a DRBtscan
tool and the proper Diagnostic Procedures manual
are recommended.
The other electronic modules that may affect mem-
ory system operation are as follows:
²Body Control Module (BCM)- Refer toBody
Control Modulein Electronic Control Modules for
more information.
²Driver Door Module (DDM)- Refer toDoor
Modulein Electronic Control Modules for more
information.
²Electronic Vehicle Information Center
(EVIC)- Refer toElectronic Vehicle Information
Centerin Overhead Console Systems for more infor-
mation.
²Passenger Door Module (PDM)- Refer to
Door Modulein Electronic Control Modules for
more information.
²Powertrain Control Module (PCM)- Refer to
Powertrain Control Modulein Electronic Control
Modules for more information.
²Radio Receiver- Refer toRadio Receiverin
Audio Systems for more information.
Refer toHeated Seat Systemfor more informa-
tion on this system. Refer toRemote Keyless Entry
Systemin Power Lock Systems for more information
on the RKE system. Refer toPower Mirrorin
Power Mirror Systems for more information on the
WJPOWER SEAT SYSTEM 8N - 19
POWER SEAT SYSTEM (Continued)

Page 517 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual mirror position potentiometers. Refer toPower Seat
TrackandPower Seat Reclinerin the Power Seat
System section of this group for more information on
the driver side power seat position potentiometers.

mirror position potentiometers. Refer toPower Seat
TrackandPower Seat Reclinerin the Power Seat
System section of this group for more information on
the driver side power seat position potentiometers.
Refer toPower Seatin Wiring Diagrams for com-
plete circuit diagrams. Following are general descrip-
tions of the remaining major components in the
factory-installed memory system.
OPERATION
OPERATION - POWER SEAT SYSTEM
The power seat system allows the driver and/or
front passenger seating positions to be adjusted elec-
trically and independently using the separate power
seat switches found on the outboard seat cushion
side shield of each front seat. See the owner's manual
in the vehicle glove box for more information on the
features, use and operation of the power seat system.
OPERATION - MEMORY SYSTEM
See the owner's manual in the vehicle glove box for
more information on the features, use and operation of
the memory system. For diagnosis of the MSM, the PCI
data bus, or the other electronic modules on the PCI
data bus that provide inputs and outputs for the mem-
ory system, the use of a DRBtscan tool and the proper
Diagnostic Procedures manual are recommended.
DRIVER AND PASSENGER DOOR MODULES
The Driver Door Module (DDM) monitors the mem-
ory switch through a hard wired circuit. It also mon-
itors the unlock messages from the Remote Keyless
Entry (RKE) receiver in the Passenger Door Module
(PDM) sent over the Programmable Communications
Interface (PCI) data bus. The DDM is programmed to
send memory recall messages and memory system
status messages over the PCI data bus to the other
electronic modules when it detects a memory recall
request.
Refer toDoor Modulein Electronic Control Mod-
ules for more information on the DDM and PDM.
ELECTRONIC VEHICLE INFORMATION CENTER
The Electronic Vehicle Information Center (EVIC)
serves as the user interface for the memory system. It
displays memory system status messages and provides
the user with the means for enabling and disabling
the many customer programmable features available
on the vehicle, including those for the memory system.
See the owner's manual in the vehicle glove box for
more information on the features, use and operation
of the EVIC. Refer toElectronic Vehicle Informa-
tion Centerin Overhead Console Systems for more
information on the EVIC.
DIAGNOSIS AND TESTING
DIAGNOSIS & TESTING - POWER SEAT
SYSTEM
Following are tests that will help to diagnose the
hard wired components and circuits of the power seat
system. However, if the vehicle is also equipped with
the optional memory system, these tests may not
prove conclusive in the diagnosis of the driver side
power seat. In order to obtain conclusive testing of
the driver side power seat with the memory system
option, the Programmable Communications Interface
(PCI) data bus network and all of the electronic mod-
ules that provide inputs to, or receive outputs from
the memory system components must be checked.
The most reliable, efficient, and accurate means to
diagnose the driver side power seat with the memory
system option requires the use of a DRBtscan tool
and the proper Diagnostic Procedures manual. The
DRBtscan tool can provide confirmation that the
PCI data bus is functional, that all of the electronic
modules are sending and receiving the proper mes-
sages on the PCI data bus, and that the memory sys-
tem is receiving the proper hard wired inputs and
relaying the proper hard wired outputs to perform its
driver side power seat functions.
Before any testing of the power seat system is
attempted, the battery should be fully-charged and
all of the power seat system wire harness connections
and pins cleaned and tightened to ensure proper cir-
cuit continuity and ground paths. For complete cir-
cuit diagrams, refer toPower Seatin Wiring
Diagrams.
With the dome lamp on, apply the power seat
switch in the direction of the failure. If the dome
lamp dims, the seat may be jamming. Check under
and behind the seat for binding or obstructions. If
the dome lamp does not dim, proceed with testing of
the individual components and circuits.
DIAGNOSIS & TESTING - MEMORY SYSTEM
Following are tests that will help to diagnose the
components and circuits that provide hard wired
inputs to the memory system. However, these tests
may not prove conclusive in the diagnosis of this sys-
tem. In order to obtain conclusive testing of the
memory system, the Programmable Communications
Interface (PCI) data bus network and all of the elec-
tronic modules that provide inputs to, or receive out-
puts from the memory system components must be
checked.
The most reliable, efficient, and accurate means to
diagnose the memory system requires the use of a
DRBtscan tool and the proper Diagnostic Proce-
dures manual. The DRBtscan tool can provide con-
firmation that the PCI data bus is functional, that all
8N - 20 POWER SEAT SYSTEMWJ
POWER SEAT SYSTEM (Continued)

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JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual of the electronic modules are sending and receiving
the proper messages on the PCI data bus, and that
the memory system is receiving the proper hard
wired inputs and relaying the proper hard wired out

of the electronic modules are sending and receiving
the proper messages on the PCI data bus, and that
the memory system is receiving the proper hard
wired inputs and relaying the proper hard wired out-
puts to perform its functions.
DRIVER SEAT SWITCH
DESCRIPTION
Two different power seat switches are used on this
vehicle, depending upon the optional power seat sys-
tem installed in the vehicle. The six-way power seats
are each equipped with a switch featuring three
switch control knobs ganged together on the outboard
seat cushion side shield (Fig. 1). The ten-way power
seats are each equipped with a switch featuring two
knobs ganged together on the outboard seat cushion
side shield (Fig. 2).
The switch units for both power seat types are
secured to the back of the seat cushion side shield
with two screws. However, the control knobs for the
six-way power seat switch unit remain installed dur-
ing switch unit removal and installation, while both
knobs for the ten-way power seat switch unit must
be removed.
The individual switches in both power seat switch
units cannot be repaired. If one switch is damaged or
faulty, the entire power seat switch unit must be
replaced.
OPERATION
The power seat tracks of both the six-way and the
ten-way power seat systems can be adjusted in six
different ways using the power seat switches. The
ten-way system has the additional power seat
recliner switch integral to the power seat switch and
also has a separate, stand-alone switch to control the
power lumbar adjuster. See the owner's manual in
the vehicle glove box for more information on the
power seat switch functions and the seat adjusting
procedures.
When a power switch control knob or knobs are
actuated, a battery feed and a ground path are
applied through the switch contacts to the power seat
track or recliner adjuster motor. The selected
adjuster motor operates to move the seat track or
recliner through its drive unit in the selected direc-
tion until the switch is released, or until the travel
limit of the adjuster is reached. When the switch is
moved in the opposite direction, the battery feed and
ground path to the motor are reversed through the
switch contacts. This causes the adjuster motor to
run in the opposite direction.
No power seat switch should be held applied in any
direction after the adjuster has reached its travel
limit. The power seat adjuster motors each contain a
self-resetting circuit breaker to protect them from
overload. However, consecutive or frequent resetting
of the circuit breaker must not be allowed to con-
tinue, or the motor may be damaged.
Fig. 1 Six-Way Power Seat Switches - Typical
1 - OUTBOARD SEAT CUSHION SIDE SHIELD
2 - POWER SEAT TRACK SWITCHES
3 - MECHANICAL SEAT BACK RECLINER LEVER
Fig. 2 Ten-Way Power Seat Switches - Typical
1 - OUTBOARD CUSHION SIDE SHIELD
2 - POWER SEAT RECLINER SWITCH
3 - POWER SEAT TRACK SWITCH
4 - POWER LUMBAR SWITCH
WJPOWER SEAT SYSTEM 8N - 21
POWER SEAT SYSTEM (Continued)

Page 519 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual DIAGNOSIS AND TESTING - DRIVER SEAT
SWITCH
For complete circuit diagrams, refer toWiring
Diagrams.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the power seat switch from the out-

Page 520 of 2199

JEEP GRAND CHEROKEE 2002 WJ / 2.G Workshop Manual REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) On models with the ten-way power seat system
only, using a push pin remover or another suitable
wide flat-bladed tool, gently pry the

REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) On models with the ten-way power seat system
only, using a push pin remover or another suitable
wide flat-bladed tool, gently pry the power seat and
power recliner switch knobs off of the switch stems
(Fig. 5).
(3) Remove the three screws that secure the out-
board seat cushion side shield to the seat cushion
frame.
(4) Pull the outboard seat cushion side shield away
from the seat cushion frame far enough to access the
power seat switch wire harness connector.
(5) Disconnect the power seat wire harness connec-
tor from the power seat switch connector receptacle.
(6) Remove the two screws that secure the power
seat switch to the inside of the outboard seat cushion
side shield (Fig. 6) or (Fig. 7).
(7) Remove the power seat switch from the out-
board seat cushion side shield.
INSTALLATION
(1) Position the power seat switch onto the out-
board seat cushion side shield.
(2) Install and tighten the two screws that secure
the power seat switch to the inside of the outboard
seat cushion side shield. Tighten the screws to 1.5
N´m (14 in. lbs.).
(3) Reconnect the power seat wire harness connec-
tor to the power seat switch connector receptacle.(4) Position the outboard seat cushion side shield
onto the seat cushion frame
(5) Install and tighten the three screws that secure
the outboard seat cushion side shield to the seat
cushion frame. Tighten the screws to 1.5 N´m (14 in.
lbs.).
(6) On models with the ten-way power seat system
only, position the power seat and power recliner
switch knobs onto the switch stems and push on
them firmly and evenly until they snap into place.
(7) Reconnect the battery negative cable.
Fig. 5 Removing Switch Control Knobs - Typical
Fig. 6 Six-Way Power Seat Switches Remove/Install
1 - SEAT SIDE SHIELD
2 - POWER SEAT SWITCH
3 - SCREWS
Fig. 7 Ten-Way Power Seat Switches Remove/Install
1 - POWER SEAT SWITCH
2 - SCREWS (2)
3 - POWER LUMBAR SWITCH
4 - SEAT CUSHION SIDE SHIELD
5 - WIRE HARNESS CONNECTOR
WJPOWER SEAT SYSTEM 8N - 23
DRIVER SEAT SWITCH (Continued)

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