2003 JEEP GRAND CHEROKEE Electronic

LICENSE PLATE LAMP UNIT
REMOVAL.............................18
INSTALLATION.........................19
LEFT MULTI-FUNCTION SWITCH
DESCRIPTION.........................19
OPERATION...........................19
DIAGNOSIS AND TESTING - LEFT MULTI -
FUNCTION SWITCH...................20
REMOVAL
REMOVAL - LEFT MULTI-FUNCTION
SWITCH............................22
REMOVAL - MULTI-FUNCTION SWITCH
MOUNTING HOUSING..................22
INSTALLATION
INSTALLATION - LEFT MULTI-FUNCTION
SWITCH............................23
INSTALLATION - MULTI-FUNCTION SWITCH
MOUNTING HOUSING..................24
PARK/TURN SIGNAL LAMP
REMOVAL - BULBS.....................25INSTALLATION - BULBS..................25
TAIL LAMP
DESCRIPTION.........................25
OPERATION...........................25
REMOVAL
REMOVAL - BULBS....................25
REMOVAL - LAMP.....................25
INSTALLATION
INSTALLATION - BULBS................26
INSTALLATION - LAMP.................26
TURN SIGNAL CANCEL CAM
DESCRIPTION.........................26
OPERATION...........................26
UNDERHOOD LAMP
REMOVAL
REMOVAL - BULB.....................27
REMOVAL - LAMP.....................27
INSTALLATION
INSTALLATION - BULB.................27
INSTALLATION - LAMP.................27
LAMPS/LIGHTING - EXTERIOR
DESCRIPTION - TURN SIGNAL & HAZARD
WARNING SYSTEM
The turn signal and hazard warning system
includes the following major components, which are
described in further detail elsewhere in this service
information:
²Combination Flasher
²Front Side Marker Lamps
²Hazard Warning Switch
²Turn Signal Cancel Cam
²Turn Signal Indicators
²Turn Signal Lamps
²Turn Signal Switch
The turn signal and hazard warning systems also
provide the following features:
²Flash Lights with Lock- This customer pro-
grammable feature flashes the hazard warning lamps
to provide optical verification that the Remote Key-
less Entry (RKE) System has received a valid Lock or
Unlock request from an RKE transmitter. (Refer to 8
- ELECTRICAL/POWER LOCKS - DESCRIPTION -
REMOTE KEYLESS ENTRY SYSTEM).
²Panic Mode Optical Alert- This feature
flashes the hazard warning lamps to provide an opti-
cal alert when the Remote Keyless Entry (RKE) Sys-
tem panic mode is activated by depressing the Panic
button on an RKE transmitter. (Refer to 8 - ELEC-
TRICAL/POWER LOCKS - DESCRIPTION -
REMOTE KEYLESS ENTRY SYSTEM).
²Turn Signal On Warning- This feature pro-
vides the vehicle operator with both visual and audi-
ble reminders when a turn signal has been left
turned on for an extended period. (Refer to 8 - ELEC-TRICAL/OVERHEAD CONSOLE/ELECTRONIC
VEHICLE INFO CENTER - DESCRIPTION).
²Vehicle Theft Security System (VTSS) Opti-
cal Alarm- This feature flashes the hazard warning
lamps to provide an optical alarm when the VTSS is
armed and activated by an unauthorized entry into
the vehicle. (Refer to 8 - ELECTRICAL/VEHICLE
THEFT SECURITY - DESCRIPTION - VEHICLE
THEFT SECURITY SYSTEM).
OPERATION - TURN SIGNAL & HAZARD
WARNING SYSTEM
The turn signal system operates on battery current
received on a fused ignition switch output (run) cir-
cuit so that the turn signals will only operate with
the ignition switch in the On position. The hazard
warning system operates on non-switched battery
current received on a fused B(+) circuit so that the
hazard warning remains operational regardless of
the ignition switch position. When the turn signal
system is activated, the circuitry of the turn signal
switch and the combination flasher will cause the
selected (right or left) turn signal indicator, front
park/turn signal lamp, front side marker lamp and
rear tail/stop/turn signal lamp to flash on and off.
When the hazard warning system is activated, the
circuitry of the hazard warning switch and the com-
bination flasher will cause both the right side and
the left side turn signal indicators, front park/turn
signal lamps, front side marker lamps and rear tail/
stop/turn signal lamps to flash on and off.
The Body Control Module (BCM) can also activate
the hazard warning system lamps by energizing the
combination flasher through a single hard wired con-
nection to the hazard warning switch sense circuit.
The BCM grounds the circuit to energize and de-en-
8L - 2 LAMPS/LIGHTING - EXTERIORWJ

ergize the combination flasher in response to mes-
sage inputs received over the Programmable
Communications Interface (PCI) data bus network.
The BCM can energize the combination flasher when
the VTSS is requested.
Vehicles equipped with the optional Electronic
Vehicle Information Center (EVIC) use turn signal
status messages received from the Electro-Mechani-
cal Instrument Cluster (EMIC) and distance mes-
sages received from the Powertrain Control Module
(PCM) over the PCI data bus to determine when the
Turn Signal On warning should be activated. The
EMIC receives hard wired inputs from the combina-
tion flasher to operate the turn signal indicators,
then sends the proper turn signal status message to
the EVIC. If a turn signal is left on for more than
about 1.6 kilometers (1 mile) of driving distance, the
EVIC will display a visual ªTurn Signal Onº message
and will send a request to the BCM over the PCI
data bus to notify the vehicle operator.
During both the turn signal and the hazard warn-
ing operation, if the exterior lamps are turned Off,
the front park/turn signal lamps and the front side
marker lamps will flash in unison. If the exterior
lamps are turned On, the front park/turn signal
lamps and the front side marker lamps will flash
alternately. Refer to the owner's manual.
DIAGNOSIS AND TESTING - TURN SIGNAL &
HAZARD WARNING SYSTEMS
When diagnosing the turn signal and hazard warn-
ing circuits, remember that high generator output
can burn out bulbs rapidly and repeatedly. If this is a
concern on the vehicle being diagnosed, test the
charging system as required.
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) Turn the ignition switch to the On position.
Actuate the turn signal switch or the hazard warning
switch. Observe the turn signal indicator lamp(s) in
the instrument cluster. If the flash rate is very high,
check for a turn signal bulb that is not lit or is verydimly lit. Repair the circuits to that lamp or replace
the faulty bulb, as required. If the turn signal indi-
cator(s) fail to light, go to Step 2.
(2) Turn the ignition switch to the Off position.
Check the ignition run fuse and the flasher fuse in
the Junction Block (JB). If OK, go to Step 3. If not
OK, repair the shorted circuit or component as
required and replace the faulty fuse(s).
(3) Check for battery voltage at the flasher fuse in
the JB. If OK, go to Step 4. If not OK, repair the
open fused B(+) circuit between the JB and the
Power Distribution Center (PDC).
(4) Turn the ignition switch to the On position.
Check for battery voltage at the ignition run fuse in
the JB. If OK, go to Step 5. If not OK, repair the
open fused ignition switch output (run) circuit
between the JB and the ignition switch.
(5) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Remove the combination flasher from the JB and
replace it with a known good unit. Reconnect the bat-
tery negative cable. Test the operation of the turn
signal and hazard warning systems. If OK, discard
the faulty combination flasher. If not OK, remove the
test flasher and go to Step 6.
(6) Turn the ignition switch to the On position.
Check for battery voltage at the fused ignition switch
output (run) circuit cavity in the JB for the combina-
tion flasher. If OK, go to Step 7. If not OK, repair the
open fused ignition switch output (run) circuit
between the combination flasher and the ignition run
fuse in the JB.
(7) Turn the ignition switch to the Off position.
Check for battery voltage at the B(+) circuit of the JB
for the combination flasher. If OK, go to Step 8. If
not OK, repair the open B(+) circuit between the
combination flasher and the flasher fuse in the JB.
(8) Disconnect and isolate the battery negative
cable. Disconnect the instrument panel wire harness
connector for the turn signal and hazard warning
switches from the multi-function switch connector.
Check for continuity between the ground circuit of
the instrument panel wire harness connector for the
left multi-function switch and a good ground. There
should be continuity. If OK, go to Step 9. If not OK,
repair the open ground circuit.
(9) Check for continuity between the hazard 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 10. If not OK, repair the shorted hazard switch
sense circuit between the multi-function switch and
the combination flasher.
(10) Check for continuity between the hazard
switch sense circuit of the JB for the combination
flasher and the instrument panel wire harness con-
WJLAMPS/LIGHTING - EXTERIOR 8L - 3
LAMPS/LIGHTING - EXTERIOR (Continued)

INSTALLATION - CHMSL
(1) Connect the wire harness connector.
(2) Position the CHMSL on liftgate.
(3) Install the screws attaching the CHMSL to the
liftgate.
COMBINATION FLASHER
DESCRIPTION
The combination flasher is located in the Junction
Block (JB) (Fig. 6). The JB is located underneath the
driver side of the instrument panel outboard of the
steering column. The combination flasher is a smart
relay that functions as both the turn signal system
and the hazard warning system flasher. The combi-
nation flasher contains active electronic Integrated
Circuitry (IC) elements. This flasher is designed to
handle the current flow requirements of the factory-
installed lighting. If supplemental lighting is added
to the turn signal lamp circuits, such as when towing
a trailer with lights, the combination flasher will
automatically try to compensate to keep the flash
rate the same.The combination flasher has nine blade-type termi-
nals that connect it to the vehicle electrical system.
Refer to the appropriate wiring information.
Because of the active electronic elements within
the combination flasher, it cannot be tested with con-
ventional automotive electrical test equipment. If the
combination flasher is believed to be faulty, test the
turn signal system and hazard warning system cir-
cuits.(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING
- EXTERIOR - DIAGNOSIS AND TESTING - TURN
SIGNAL & HAZARD WARNING SYSTEM). The com-
bination flasher cannot be repaired or adjusted and,
if faulty or damaged, it must be replaced.
OPERATION
The combination flasher controls the following
inputs and outputs: B(+), fused ignition switch out-
put, left turn switch sense, right turn switch sense,
hazard switch sense, left front turn signal circuit,
right front turn signal circuit, left rear turn signal
circuit and right rear turn signal circuit. Constant
battery voltage is supplied to the flasher so that it
can perform the hazard warning function, and igni-
tion switched battery voltage is supplied for the turn
signal function. However, when the flasher is idle no
current is drawn through the module. The unit does
not become active until it is provided a signal ground
from the turn signal switch, hazard warning switch
or the Body Control Module (BCM).
The IC within the combination flasher (Fig. 7) con-
tains the logic that controls the flasher operation and
the flash rate. When a bulb is burnt out, or when a
circuit for a lamp is open, the turn signal flash rate
will increase. However, an open lamp circuit or burnt
out bulb does not change the hazard warning flash
rate.
Fig. 6 Combination Flasher
1 - COMBINATION FLASHER
2 - JUNCTION BLOCK
WJLAMPS/LIGHTING - EXTERIOR 8L - 7
CENTER HIGH MOUNTED STOP LAMP (Continued)

CONDITION POSSIBLE CAUSES CORRECTION
3. Faulty headlamp switch. 3. Refer to BCM diagnostics.
4. Blown fuse for headlamps. 4. Replace fuse refer to Electrical, Wiring
Information.
5. Broken connector terminal or wire
splice in headlamp circuit.5. Repair connector terminal or wire splice.
6. Both headlamp bulbs defective. 6. Replace both headlamp bulbs.
*Canada vehicles must have lamps ON.
FOG LAMP
CONDITION POSSIBLE CAUSES CORRECTION
FOG LAMPS ARE DIM
WITH ENGINE IDLING
OR IGNITION TURNED
OFF.1. Loose or corroded battery cables. 1. Clean and secure battery cable clamps
and posts.
2. Loose or worn generator drive belt. 2. Adjust or replace generator drive belt.
3. Charging system output too low. 3. Test and repair charging system. Refer to
Electrical, Charging,
4. Battery has insufficient charge. 4. Test battery state-of -charge. Refer to
Electrical, Battery System.
5. Battery is sulfated or shorted. 5. Load test battery. Refer to Electrical,
Battery System.
6. Poor lighting circuit Z1-ground. 6. Test for voltage drop across Z1-ground
locations. Refer to Electrical, Wiring
Information.
FOG LAMP BULBS BURN
OUT FREQUENTLY1. Charging system output too high. 1. Test and repair charging system. Refer to
Electrical, Charging.
2. Loose or corroded terminals or
splices in circuit.2. Inspect and repair all connectors and
splices. Refer to Electrical, Wiring
Information.
FOG LAMPS ARE DIM
WITH ENGINE RUNNING
ABOVE IDLE1. Charging system output too low. 1. Test and repair charging system. Refer to
Electrical, Charging.
2. Poor lighting circuit Z1-ground. 2. Test for voltage drop across Z1-ground
locations. Refer to Electrical, Wiring
Information.
3. High resistance in fog lamp circuit. 3. Test amperage draw of fog lamp circuit.
FOG LAMPS FLASH
RANDOMLY1. Poor lighting circuit Z1-ground. 1. Test for voltage drop across Z1-ground
locations. Refer to Electrical, Wiring
Information.
2. High resistance in fog lamp circuit. 2. Test amperage draw of fog lamp circuit.
3. Faulty multifunction switch. 3. Refer to Electrical, Electronic Control
Modules.
4. Loose or corroded terminals or
splices in circuit.4. Inspect and repair all connectors and
splices. Refer to Electrical, Wiring
Information.
WJLAMPS/LIGHTING - EXTERIOR 8L - 13
HEADLAMP (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)

MESSAGE SYSTEMS
TABLE OF CONTENTS
page page
OVERHEAD CONSOLE
DESCRIPTION..........................1
OPERATION............................1
STANDARD PROCEDURE
STANDARD PROCEDURE - MODULE LAMP
REPLACEMENT.......................1
STANDARD PROCEDURE - COURTESY
LAMP REPLACEMENT..................1
STANDARD PROCEDURE - MODULE LENS
REPLACEMENT.......................2
STANDARD PROCEDURE - ELECTRONIC
VEHICLE INFORMATION CENTER
PROGRAMMING.......................2
STANDARD PROCEDURE - COMPASS
DEMAGNETIZING......................4
STANDARD PROCEDURE - COMPASS
CALIBRATION.........................5
STANDARD PROCEDURE - COMPASS
VARIATION ADJUSTMENT................5
REMOVAL.............................5
INSTALLATION..........................6
SPECIAL TOOLS
OVERHEAD CONSOLE SYSTEMS.........6
ELECTRONIC VEHICLE INFO CENTER
DESCRIPTION..........................6OPERATION............................9
DIAGNOSIS AND TESTING - ELECTRONIC
VEHICLE INFORMATION CENTER.........9
STANDARD PROCEDURE - TIRE PRESSURE
SYSTEM TEST.......................10
REMOVAL.............................10
INSTALLATION.........................10
UNIVERSAL TRANSMITTER
DESCRIPTION.........................11
OPERATION...........................11
DIAGNOSIS AND TESTING - UNIVERSAL
TRANSMITTER.......................11
AMBIENT TEMP SENSOR
DESCRIPTION.........................12
OPERATION...........................12
DIAGNOSIS AND TESTING
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR...............12
DIAGNOSIS AND TESTING - AMBIENT
TEMPERATURE SENSOR CIRCUIT........12
REMOVAL.............................12
INSTALLATION.........................13
OVERHEAD CONSOLE
DESCRIPTION
An overhead console is standard factory-installed
equipment on this model. The overhead console
includes the Electronic Vehicle Information Center
(EVIC) and two reading and courtesy lamps (Fig. 1).
On vehicles equipped with a power sunroof option,
the overhead console also houses the power sunroof
switch between the two reading and courtesy lamps.
The overhead console is mounted with one screw and
two snap-clips to a molded plastic retainer bracket
located above the headliner. The retainer bracket is
secured with adhesive to the inside surface of the
roof panel.
Following are general descriptions of the major
components used in the overhead console. Refer to
Overhead Consolein Wiring Diagrams for complete
circuit diagrams.
OPERATION
See the owner's manual in the vehicle glove box for
more information on the use and operation of the
various overhead console features.
STANDARD PROCEDURE
STANDARD PROCEDURE - MODULE LAMP
REPLACEMENT
(1) Remove the overhead console (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - REMOV-
AL).
(2) Using a flat blade screwdriver twist out socket/
lamp (Fig. 2).
(3) Replace lamp(s) as necessary.
STANDARD PROCEDURE - COURTESY LAMP
REPLACEMENT
(1) Open hood, disconnect and isolate the negative
battery cable.
WJMESSAGE SYSTEMS 8M - 1

(2) Remove the overhead console from the head-
liner (Refer to 8 - ELECTRICAL/OVERHEAD CON-
SOLE - REMOVAL).(3) Remove the lamp and socket assembly from the
overhead console.
(4) Remove the lamp bulb by pulling it straight
out of its socket.
STANDARD PROCEDURE - MODULE LENS
REPLACEMENT
(1) Remove the overhead console (Refer to 8 -
ELECTRICAL/OVERHEAD CONSOLE - REMOV-
AL).
(2) Remove the electronics module from the over-
head console. Refer to the procedure in this section.
(3) Unsnap the lens from the module and replace
lens as necessary.
STANDARD PROCEDURE - ELECTRONIC
VEHICLE INFORMATION CENTER
PROGRAMMING
EVIC PROGRAMMING MODE
The Electronic Vehicle Information Center (EVIC)
provides the vehicle operator with a user interface,
which allows the selection of several optional cus-
tomer programmable electronic features to suit indi-
vidual preferences. The EVIC must be placed into its
programming mode in order to view or change the
programmable features. To enter the EVIC program-
ming mode and to view or change the selected pro-
grammable features options, proceed as follows:
(1) Turn the ignition switch to the On position.
(2) Depress and release the Menu push button.
The first item in the programmable features menu
list will appear in the EVIC display.
(3) Momentarily depress and release the Menu
push button to step through the programmable fea-
tures list. Each programmable feature and its cur-
rently selected option will appear on the EVIC
display in the sequence shown in the Programmable
Features list that follows.
(4) Momentarily depress and release the Step push
button to step through the available options for the
programmable feature being displayed.
(5) The option that last appears in the display
with a programmable feature before exiting the pro-
gramming mode, becomes the newly selected pro-
grammable feature option.
(6) The EVIC exits the programming mode and
returns to its normal operating mode when the C/T
push button is depressed or when the end of the pro-
grammable features menu list is reached, whichever
occurs first.
Fig. 1 Overhead Console
1 - POWER SUNROOF SWITCH (IF EQUIPPED)
2 - READING AND COURTESY LAMPS
3 - UNIVERSAL GARAGE DOOR OPENER PUSH BUTTONS (IF
EQUIPPED)
4 - SCREW
5 - ELECTRONIC VEHICLE INFORMATION CENTER PUSH
BUTTONS
Fig. 2 Top of Overhead Console
1 - OVERHEAD CONSOLE HOUSING
2 - EVIC MODULE
3 - ILLUMINATION LAMPS
4 - SCREWS (4)
8M - 2 MESSAGE SYSTEMSWJ
OVERHEAD CONSOLE (Continued)

tip of the tool is at least 61 centimeters (2 feet) from
the roof panel, disconnect the tool.
(11) Calibrate the compass and adjust the compass
variance (Refer to 8 - ELECTRICAL/OVERHEAD
CONSOLE - STANDARD PROCEDURE).
STANDARD PROCEDURE - COMPASS
CALIBRATION
CAUTION: Do not place any external magnets, such
as magnetic roof mount antennas, in the vicinity of
the compass. Do not use magnetic tools when ser-
vicing the overhead console.
The electronic compass unit features a self-cali-
brating design, which simplifies the calibration pro-
cedure. This feature automatically updates the
compass calibration while the vehicle is being driven.
This allows the compass unit to compensate for small
changes in the residual magnetism that the vehicle
may acquire during normal use. If the compass read-
ings appear to be erratic or out of calibration, per-
form the following calibration procedure. Also, new
service replacement Electronic Vehicle Information
Center (EVIC) modules must have their compass cal-
ibrated using this procedure. Do not attempt to cali-
brate the compass near large metal objects such as
other vehicles, large buildings, or bridges; or, near
overhead or underground power lines.
NOTE: Whenever an EVIC module is replaced, the
variance number must also be reset. Refer to Com-
pass Variation Adjustment in this group.
Calibrate the compass manually as follows:
(1) Turn the ignition switch to the On position. If
the compass/temperature data is not currently being
displayed, momentarily depress and release the C/T
push button to reach the compass/temperature dis-
play.
(2) Depress the Reset push button and hold the
button down until ªCALº appears in the display. This
takes about ten seconds, and appears about five sec-
onds after ªVARIANCE = XXº is displayed.
(3) Release the Reset push button.
(4) Drive the vehicle on a level surface, away from
large metal objects and power lines, through one
complete circle at between five and eight kilometers-
per-hour (three and five miles-per-hour) in not less
than 20 seconds. The ªCALº message will disappear
from the display to indicate that the compass is now
calibrated.
NOTE: If the ªCALº message remains in the display,
either there is excessive magnetism near the com-
pass, or the unit is faulty. Repeat the calibration
procedure one more time.NOTE: If the wrong direction is still indicated in the
compass display, the area selected for calibration
may be too close to a strong magnetic field. Repeat
the calibration procedure in another location.
STANDARD PROCEDURE - COMPASS
VARIATION ADJUSTMENT
Compass variance, also known as magnetic decli-
nation, is the difference in angle between magnetic
north and true geographic north. In some geographic
locations, the difference between magnetic and geo-
graphic north is great enough to cause the compass
to give false readings. If this problem occurs, the
compass variance setting may need to be changed.
To set the compass variance:
(1) Using the Variance Settings map, find your
geographic location and note the zone number (Fig.
4).
(2) Turn the ignition switch to the On position. If
the compass/temperature data is not currently being
displayed, momentarily depress and release the C/T
push button to reach the compass/temperature dis-
play.
(3) Depress the Reset push button and hold the
button down until ªVARIANCE = XXº appears in the
display. This takes about five seconds.
(4) Release the Reset push button. ªVARIANCE
=XX º will remain in the display. ªXXº equals the cur-
rent variance zone setting.
(5) Momentarily depress and release the Step push
button to step through the zone numbers, until the
zone number for your geographic location appears in
the display.
(6) Momentarily depress and release the Reset
push button to enter the displayed zone number into
the EVIC module memory.
(7) Confirm that the correct directions are now
indicated by the compass.
REMOVAL
(1) Disconnect and isolate the battery negative
cable.
(2) Remove the screw that secures the front of the
overhead console to the front of the overhead console
retainer bracket.
(3) Insert the fingertips of both hands between the
headliner and the sides of the overhead console hous-
ing in the area near the reading and courtesy lamps.
(4) Pull downward on the sides of the overhead
console housing firmly and evenly to disengage the
two snap clips that secure the rear of the unit from
their receptacles in the overhead console retainer
bracket.
(5) Lower the overhead console from the headliner
far enough to access the wire harness connectors.
WJMESSAGE SYSTEMS 8M - 5
OVERHEAD CONSOLE (Continued)