2003 JEEP GRAND CHEROKEE Failure

²Hazard Warning Control- The hazard warn-
ing push button is pressed down to activate the haz-
ard warning system, and pressed down again to turn
the system off. The left multi-function switch pro-
vides a ground to the hazard warning sense input of
the combination flasher to control activation of the
hazard warning lamps.
²Headlamps- The Body Control Module (BCM)
monitors the left multi-function switch then, based
upon that multiplexed input, controls an output to
the headlamp low or high beam relays to illuminate
or extinguish the headlamps.
²Headlamp Beam Selection- The Body Control
Module (BCM) monitors the left multi-function
switch then, based upon that switched ground input,
controls an output to the headlamp low or high beam
relays to activate the selected headlamp beam.
²Headlamp Optical Horn- The Body Control
Module (BCM) monitors the left multi-function
switch then, based upon that switched ground input,
controls an output to the headlamp high beam relay
to activate the headlamp high beams.
²Park Lamps- The Body Control Module (BCM)
monitors the left multi-function switch then, based
upon that multiplexed input, controls an output to
the park lamp relay to illuminate or extinguish the
parking lamps.
²Rear Fog Lamps- The Body Control Module
(BCM) monitors the left multi-function switch then,
based upon that multiplexed input, controls an out-
put to the rear fog lamp relay to illuminate or extin-
guish the rear fog lamps.
²Turn Signal Control- The left multi-function
switch control stalk actuates the turn signal switch.
The Body Control Module (BCM) monitors the left
multi-function switch then, based upon that multi-
plexed input, provides a variable voltage output to
control the lighting of the turn signals.
Following are descriptions of the how the left
multi-function switch operates to control the many
interior lighting functions and features it provides:
²Panel Lamps Dimming- The Body Control
Module (BCM) monitors the left multi-function
switch then, based upon that multiplexed input, pro-
vides a variable voltage output through several panel
lamps driver circuits to control the lighting of many
incandescent panel lamps. The BCM also sends panel
lamps dimming messages over the Programmable
Communications Interface (PCI) data bus to other
modules to control Display lighting levels in those
modules.²Interior Lamps Defeat- The Body Control
Module (BCM) monitors the left multi-function
switch then, based upon that multiplexed input,
internally disables the function the BCM normally
provides to control the illumination of the interior
lamps.
²Interior Lamps On- The Body Control Module
(BCM) monitors the left multi-function switch then,
based upon that multiplexed input, provides a control
output to activate all of the interior lamp circuits.
²Parade Mode- The Body Control Module
(BCM) monitors the left multi-function switch then,
based upon that multiplexed input, provides a volt-
age output through several panel lamps driver cir-
cuits to control the lighting of many incandescent
panel lamps. The BCM also sends panel lamps dim-
ming messages over the Programmable Communica-
tions Interface (PCI) data bus to other modules on
the bus to control lighting levels in those modules.
DIAGNOSIS AND TESTING - LEFT MULTI -
FUNCTION SWITCH
Refer to the appropriate 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 ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Disconnect and isolate the battery negative
cable. Disconnect the instrument panel wire harness
connector from the multi-function switch connector.
(2) Using an ohmmeter, perform the continuity
and resistance tests at the terminals in the multi-
function switch connector as shown in the Left Multi-
Function Switch Test chart (Fig. 23).
8L - 20 LAMPS/LIGHTING - EXTERIORWJ
LEFT MULTI-FUNCTION SWITCH (Continued)

(3) If the multi-function switch fails any of the
continuity or resistance tests, replace the switch.
REMOVAL
REMOVAL - LEFT MULTI-FUNCTION SWITCH
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.
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the lower tilting steering column
shroud (Fig. 24).
(3) Unsnap the two halves of the steering column
shroud, and remove.
(4) Disconnect the instrument panel wire harness
connector from the switch connector.
(5) Remove the screws that secure the left multi-
function switch to the housing (Fig. 25).
(6) Remove the left multi-function switch.
REMOVAL - MULTI-FUNCTION SWITCH
MOUNTING HOUSING
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.
NOTE: Before starting this procedure, be certain to
turn the steering wheel until the front wheels are in
the straight-ahead position.(1) Disconnect and isolate the battery negative
cable.
Fig. 24 Steering Column Shrouds Remove/Install
1 - UPPER TILTING COLUMN SHROUD
2 - FIXED COLUMN SHROUD
3 - LOWER TILTING COLUMN SHROUD
4 - SCREW
Fig. 25 Left Multi-Function Switch Remove/Install
1 - SCREW (2)
2 - STEERING COLUMN
3 - MULTI-FUNCTION SWITCH MOUNTING HOUSING
4 - LEFT MULTI-FUNCTION SWITCH
8L - 22 LAMPS/LIGHTING - EXTERIORWJ
LEFT MULTI-FUNCTION SWITCH (Continued)

(2) Remove the clockspring from the multi-function
switch mounting housing. (Refer to 8 - ELECTRI-
CAL/RESTRAINTS/CLOCKSPRING - REMOVAL).
(3) Remove the left multi-function switch from the
multi-function switch mounting housing. (Refer to 8 -
ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
LEFT MULTI-FUNCTION SWITCH - REMOVAL -
LEFT MULTI-FUNCTION SWITCH).
(4) Remove the right multi-function switch from
the multi-function switch mounting housing. (Refer
to 8 - ELECTRICAL/WIPERS/WASHERS/RIGHT
MULTI-FUNCTION SWITCH - REMOVAL).
(5) Remove the screw that secures the multi-func-
tion switch mounting housing to the steering column
housing (Fig. 26).
(6) Remove the multi-function switch mounting
housing (Fig. 27).
INSTALLATION
INSTALLATION - LEFT MULTI-FUNCTION
SWITCH
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 AIRBAGSYSTEM. FAILURE TO TAKE THE PROPER PRE-
CAUTIONS COULD RESULT IN ACCIDENTAL AIR-
BAG DEPLOYMENT AND POSSIBLE PERSONAL
INJURY.
(1) Position the left multi-function switch onto the
housing (Fig. 28).
(2) Install and tighten the screws that secure the
left multi-function switch housing. Tighten the
screws to 2.5 N´m (22 in. lbs.).
(3) Reconnect the instrument panel wire harness
connector to the switch connector.
Fig. 26 Multi-Function Switch Mounting Housing
Screw Remove/Install
1 - CLOCK SPRING
2 - SCREW
3 - MULTI-FUNCTION SWITCH MOUNTING HOUSING
Fig. 27 Multi-Function Switch Mounting Housing
Remove/install
1 - MULTI-FUNCTION SWITCH ASSEMBLY
2 - CLOCKSPRING
Fig. 28 Left Multi-Function Switch Remove/Install
1 - SCREW (2)
2 - STEERING COLUMN
3 - MULTI-FUNCTION SWITCH MOUNTING HOUSING
4 - LEFT MULTI-FUNCTION SWITCH
WJLAMPS/LIGHTING - EXTERIOR 8L - 23
LEFT MULTI-FUNCTION SWITCH (Continued)

(4) Position the lower tilting steering column
shroud to the underside of the steering column (Fig.
29).
(5) Install and tighten the screw that secures the
lower steering column shroud housing. Tighten the
screw to 1.9 N´m (17 in. lbs.).
(6) Align the upper tilting steering column shroud
to the lower shroud and snap the two shroud halves
together.
(7) Reconnect the battery negative cable.
INSTALLATION - MULTI-FUNCTION SWITCH
MOUNTING HOUSING
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.
NOTE: Before starting this procedure, be certain
that the front wheels are still in the straight-ahead
position.
(1) Rotate the turn signal cancel cam in the multi-
function switch housing until the alignment hole in
the one cam lobe is aligned with the alignment hole
in the back of the housing. The oblong hole in the
hub of the cam should now be at the top, and the
locating tab in the hub of the cam should be at the
bottom (Fig. 30).
(2) Position the multi-function switch housing onto
the top of the steering column. The locating tab in
the hub of the turn signal cancel cam must be
engaged with the alignment groove in the bottom of
the upper steering column shaft.
(3) Install and tighten the screw that secures the
multi-function switch housing to the top of the col-
umn housing (Fig. 31). Tighten the screw to 1.9 N´m
(17 in. lbs.).
(4) Reinstall the right multi-function switch onto
the multi-function switch housing. (Refer to 8 -
ELECTRICAL/WIPERS/WASHERS/RIGHT MULTI-
FUNCTION SWITCH - INSTALLATION).
(5) Reinstall the left multi-function switch onto the
multi-function switch housing. (Refer to 8 - ELEC-
TRICAL/LAMPS/LIGHTING - EXTERIOR/LEFT
Fig. 29 Steering Column Shrouds Remove/Install
1 - UPPER TILTING COLUMN SHROUD
2 - FIXED COLUMN SHROUD
3 - LOWER TILTING COLUMN SHROUD
4 - SCREW
Fig. 30 Turn Signal Cancel Cam Alignment
1 - ALIGNMENT HOLE
2 - MULTI-FUNCTION SWITCH MOUNTING HOUSING
3 - ALIGNMENT HOLE
4 - TURN SIGNAL CANCEL CAM
5 - LOCATING TAB
6 - WASHER
7 - TURN SIGNAL SWITCH CANCEL ACTUATOR
8L - 24 LAMPS/LIGHTING - EXTERIORWJ
LEFT MULTI-FUNCTION SWITCH (Continued)

wired between a body ground, the Body Control Mod-
ule (BCM) and the rear wiper motor module through
the liftgate and body wire harnesses.
The liftgate flip-up glass ajar switch cannot be
adjusted or repaired and, if faulty or damaged, the
liftgate flip-up glass latch unit must be replaced.
(Refer to 23 - BODY/DECKLID/HATCH/LIFTGATE/
TAILGATE/FLIP-UP GLASS LATCH - REMOVAL)
for the service procedures. For complete circuit dia-
grams, refer to the appropriate wiring information.
DESCRIPTION - LIFTGATE AJAR SWITCH
The two liftgate ajar switches are integral to the
two liftgate latch mechanisms. The two liftgate ajar
switches are actuated by the liftgate latch mecha-
nisms, and are hard wired with each other between a
body ground and the Body Control Module (BCM)
through the liftgate and body wire harnesses.
The liftgate ajar switches cannot be adjusted or
repaired and, if faulty or damaged, the liftgate latch
unit must be replaced. (Refer to 23 - BODY/DECK-
LID/HATCH/LIFTGATE/TAILGATE/LATCH -
REMOVAL) for the service procedures. For complete
circuit diagrams, refer to the appropriate wiring
information.
OPERATION
OPERATION - DOOR AJAR SWITCH
The front door ajar switches close a path to ground
for the DDM or the PDM when a front door is
opened, and opens the ground path when a front door
is closed. The rear door ajar switches close a path to
ground for the BCM when a rear door is opened, and
opens the ground path when a rear door is closed.
The DDM, PDM, or BCM read the switch status then
send the proper switch status messages to other
modules over the Programmable Communications
Interface (PCI) data bus network. The door ajar
switch status message is used by the BCM as an
input for Vehicle Theft Security System (VTSS) oper-
ation.
OPERATION - FLIP UP GLASS AJAR SWITCH
The liftgate flip-up glass ajar switch can close a
path to ground for the BCM and the rear wiper
motor module when the liftgate flip-up glass is
opened, and opens the ground path when the liftgate
flip-up glass is closed. The rear wiper motor module
uses the liftgate flip-up glass ajar switch input to
control the rear wiper operation, and will park the
rear wiper blade if this input indicates that the lift-
gate flip-up glass is ajar. The BCM reads the switch
status then sends the proper switch status message
to other modules over the Programmable Communi-cations Interface (PCI) data bus network. The liftgate
flip-up glass ajar switch status message is used by
the BCM as an input for Vehicle Theft Security Sys-
tem (VTSS) operation.
OPERATION - LIFTGATE AJAR SWITCH
Each of the liftgate ajar switches can close a path
to ground for the BCM when the liftgate is opened,
and opens the ground path when the liftgate is
closed. The BCM reads the switch status then sends
the proper switch status message to other modules
over the Programmable Communications Interface
(PCI) data bus network. The liftgate ajar switch sta-
tus message is used by the BCM as an input for
Vehicle Theft Security System (VTSS) operation.
DIAGNOSIS AND TESTING - DOOR AJAR
SWITCH
The following diagnosis and testing is only
for the chime functions. For interior lamp diag-
nosis, refer to the appropriate wiring informa-
tion.The driver door ajar switch is hard wired to the
Driver Door Module (DDM). The DDM communicates
the switch status to the other modules in the vehicle
on the Programmable Communications Interface
(PCI) data bus network. The following test will diag-
nose a faulty driver door ajar switch and circuits. 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) Check that the interior lighting switch on the
control stalk of the left multi-function switch is not
in the dome lamp disable position. Open the driver
side front door and note whether the interior lamps
light. They should light. If OK, refer to Key-In Igni-
tion Switch in the Diagnosis and Testing section of
this group for further diagnosis of the chime warning
system. If not OK, go to Step 2.
(2) Disconnect and isolate the battery negative
cable. Remove the trim panel from the driver front
door and disconnect the 4-way door wire harness con-
nector from the front door latch connector. Check for
continuity between the ground circuit of the 4-way
door wire harness connector and a good ground.
There should be continuity. If OK, go to Step 3. If not
OK, repair the ground circuit.
8L - 30 LAMPS/LIGHTING - INTERIORWJ
DOOR AJAR SWITCH (Continued)

(3) Disconnect the door wire harness connector
from the Driver Door Module (DDM) connector.
Check for continuity between the driver door ajar
switch sense circuit of the door wire harness connec-
tor for the DDM and a good ground. There should be
no continuity. If OK, go to Step 4. If not OK, repair
the shorted driver door ajar switch sense circuit.
(4) Check for continuity between the driver door
ajar switch sense circuit of the door wire harness
connector for the DDM and the 4-way door wire har-
ness connector for the front door latch. There should
be continuity. If OK, go to Step 5. If not OK, repair
the open driver door ajar switch sense circuit.
(5) Check for continuity between the ground cir-
cuit terminal and the driver door ajar switch sense
circuit terminal of the front door latch connector.
There should be continuity with the driver side front
door open, and no continuity with the door closed. If
OK, use a DRBIIItscan tool and the proper Diagnos-
tic Procedures manual to test the operation of the
PCI data bus and the DDM. If not OK, replace the
faulty driver side front door latch unit.
GLOVE BOX LAMP/SWITCH
REMOVAL
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.
(2) Roll down the glove box from the instrument
panel.(Refer to 23 - BODY/INSTRUMENT PANEL/
GLOVE BOX - REMOVAL) for the procedures.
(3) Remove the lower right center bezel from the
instrument panel.(Refer to 23 - BODY/INSTRU-
MENT PANEL - REMOVAL) for the procedures.
(4) Reach through the glove box opening and
depress the retaining latches on the top and bottom
of the glove box lamp and switch housing.
(5) While holding the retaining latches depressed,
push the glove box lamp and switch out through the
mounting hole (Fig. 1).
(6) Disconnect the instrument panel wire harness
connector from the glove box lamp and switch con-
nector.
(7) Remove the glove box lamp and switch.
INSTALLATION
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) Position the glove box lamp and switch to the
instrument panel.
(2) Reconnect the instrument panel wire harness
connector to the glove box lamp and switch connector.
(3) Align the glove box lamp and switch housing
with the mounting hole in the instrument panel
glove box opening upper reinforcement.
(4) Push the glove box lamp and switch into the
mounting hole until the retaining latches are fully
engaged.
(5) Install the lower right center bezel onto the
instrument panel. (Refer to 23 - BODY/INSTRU-
MENT PANEL - INSTALLATION) for the proce-
dures.
(6) Roll the glove box back up into the instrument
panel.(Refer to 23 - BODY/INSTRUMENT PANEL/
GLOVE BOX - INSTALLATION) for the procedures.
(7) Reconnect the battery negative cable.
Fig. 1 Glove Box Lamp and Switch Remove/Install
1 - GLOVE BOX OPENING UPPER REINFORCEMENT
2 - WIRE HARNESS CONNECTOR
3 - GLOVE BOX LAMP & SWITCH
4-LATCH
5 - MOUNTING HOLE
WJLAMPS/LIGHTING - INTERIOR 8L - 31
DOOR AJAR SWITCH (Continued)

data bus messages are being received for initial oper-
ation. Initiate the self-diagnostic test as follows:
(1) With the ignition switch in the Off position,
simultaneously depress and hold the C/T button and
the Reset button.
(2) Turn the ignition switch to the On position.
(3) Continue to hold both buttons depressed until
the EVIC software version information is displayed,
then release both buttons.
(4) Following completion of these tests, the EVIC
module will display one of the following messages:
a.Pass Self Test- Momentarily depress and
release the Reset button to return to the compass/
temperature/trip computer display mode. The EVIC
module is working properly.
b.Failed Self Test- The EVIC module has an
internal failure. The EVIC module is faulty and must
be replaced.
c.Not Receiving J1850 Message- The EVIC
module is not receiving proper message input
through the PCI data bus. This can result from one
or more faulty electronic modules in the vehicle, or
from a faulty PCI data bus. The use of a DRB scan
tool and the proper Diagnostic Procedures manual
are required for further diagnosis.
NOTE: If the compass functions, but accuracy is
suspect, it may be necessary to perform a variation
adjustment. This procedure allows the compass
unit to accommodate variations in the earth's mag-
netic field strength, based on geographic location.
Refer to Compass Variation Adjustment in the Stan-
dard Procedures section of this group.
NOTE: If the compass reading displays a blank, and
only ªCALº appears in the display, demagnetizing
may be necessary to remove excessive residual
magnetic fields from the vehicle. Refer to Compass
Demagnetizing in the Standard Procedures section
of this group.
STANDARD PROCEDURE - TIRE PRESSURE
SYSTEM TEST
The following test can be used to verify two func-
tions. One, that the tire pressure sensors are trans-
mitting properly and two, the EVIC module is
receiving these transmissions accordingly.
(1) Retrain the tire sensors (Refer to 22 - TIRES/
WHEELS/TIRE PRESSURE MONITORING/SEN-
SOR - STANDARD PROCEDURE). The tire sensors
must be retrained in order to set the proper trans-
mitting time cycle (twice a minute), failure to retrain
the sensors will cause a much slower transmitting
time cycle (once a hour).(2) Using the STEP button on the overhead con-
sole, scroll to the blank display, then press the
RESET button for five seconds, a beep will sound
indicating the start of this test. The vehicle icon and
transmission counters will now be displayed, (same
display as individual tire pressure except counters
replace tire pressure values).
(3) Upon entering the test mode, the EVIC will
clear the sensor counter and each time a sensor sig-
nal for a road tire is received, the EVIC will update
the counter value (vehicle must be driven at 25 mph
to transmit). The counter values should all read the
same value. If any of the road tires indicate a differ-
ent value than another tire sensor, this is a sign of a
problem. Replace the appropriate tire sensor and
retest the system. This test will continue until any of
the overhead console buttons are pressed or the igni-
tion is turned off.
NOTE: Pressing the RESET button during the test
will sound a beep and reset all the counter values
back to zero.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the overhead console from the head-
liner (Refer to 8 - ELECTRICAL/OVERHEAD CON-
SOLE - REMOVAL).
(3) Remove the four screws that secure the Elec-
tronic Vehicle Information Center (EVIC) module to
the overhead console housing (Fig. 5).
(4) Remove the EVIC module from the overhead
console housing.
INSTALLATION
(1) Position the EVIC module onto the overhead
console housing.
(2) Install and tighten the four screws that secure
the EVIC module to the overhead console housing.
Tighten the screws to 0.9 N´m (8 in. lbs.).
(3) Install the overhead console onto the headliner
(Refer to 8 - ELECTRICAL/OVERHEAD CONSOLE -
INSTALLATION).
(4) Reconnect the battery negative cable.
NOTE: If a new EVIC module has been installed, the
compass will have to be calibrated and the variance
set. Refer to Compass Variation Adjustment and
Compass Calibration in the Service Procedures sec-
tion of this group for the procedures.
8M - 10 MESSAGE SYSTEMSWJ
ELECTRONIC VEHICLE INFO CENTER (Continued)

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)