tesy lamps and if the vehicle is equipped with a
power liftgate or power sliding door(s) the overhead
console will also include switches for these features.
The overhead console is mounted with one screw and
two snap clips to a molded plastic retainer bracket
located above the headliner.

DESCRIPTION - COMPASS

All overhead consoles include compass information.

While in the compass/temperature mode, the com-
pass will display the direction in which the vehicle is
pointed using the eight major compass headings
(Examples: north is N, northeast is NE). The self-cal-

ibrating compass unit requires no adjusting in nor-
mal use. The only calibration that may be necessary
is to drive the vehicle in three complete circles at 5
to 8 kilometers-per-hour (3 to 5 miles-per-hour), on
level ground, for a minimum of forty-eight seconds.
This will reorient the compass unit to its vehicle.

The compass unit will also compensate for magne-

tism the vehicle may acquire during normal use.
However, avoid placing anything magnetic directly on
the roof of the vehicle. Magnetic mounts for an
antenna, a repair order hat, or a funeral procession
flag can exceed the compensating ability of the com-
pass unit if placed on the roof panel. The use of mag-
netic tools on the fasteners that hold the overhead
console assembly to the roof header can also affect
compass operation. If the compass operation is
erratic and roof magnetization is suspected (Refer to
8 - ELECTRICAL/OVERHEAD CONSOLE - STAN-
DARD PROCEDURE - COMPASS DEMAGNETIZ-
ING).

MESSAGE SYSTEMS

8M - 1

DESCRIPTION - TEMPERATURE

All overhead consoles include temperature informa-

tion. The temperature displays the outside ambient
temperature in whole degrees. The temperature dis-
play can be toggled from Fahrenheit to Celsius by
selecting the desired U.S./Metric option from the cus-
tomer programmable features. The displayed temper-
ature is not an instant reading of conditions, but an
average temperature. It may take the temperature
display several minutes to respond to a major tem-
perature change, such as driving out of a heated
garage into winter temperatures.

When the ignition switch is turned to the Off posi-

tion, the last displayed temperature reading stays in
the electronic control modules (CMTC, EVIC) mem-
ory. When the ignition switch is turned to the On
position again, the electronic module will display the
memory temperature for one minute; then update the
display to the current average temperature reading
within five minutes.

The temperature function is supported by an ambi-

ent temperature sensor. The sensor is mounted near
the front and center of the vehicle, and is hard wired
to the Powertrain Control Module (PCM). The PCM
sends temperature status messages to the module
over the Programmable Communication Interface
(PCI) data bus circuit.

DIAGNOSIS AND TESTING

OVERHEAD CONSOLE

Any diagnosis of the overhead console should

begin with the use of the DRB III

t diagnostic

tool. For information on the use of the DRB
III

t, refer to the appropriate Diagnostic Proce-

dures information.

If the problem with the overhead console is an

inaccurate or dashed (- -) display, refer to SELF-DI-
AGNOSTIC TEST. If the problem with the overhead
console is incorrect Vacuum Fluorescent Display
(VFD) dimming levels, use a DRB III

t scan tool and

the proper diagnostic procedures information to test
for

the

correct

dimming

message

inputs

being

received from the Body Control Module (BCM) or
Front Control Module (FCM) over the Programmable
Communications Interface (PCI) data bus circuit. If
the problem is a no-display condition, use the follow-
ing procedures.

Inspect the related wiring harness connectors for

broken, bent, pushed out, or corroded terminals.
Refer to the appropriate wiring information.

(1) Check the fused B(+) fuse in the integrated

power module. If OK, go to Step 2. If not OK, repair
the shorted circuit or component as required and
replace the faulty fuse.

(2) Check for battery voltage at the fused B(+) fuse

in the integrated power module. If OK, go to Step 3.
If not OK, repair the open fused B(+) circuit to the
fused B(+) fuse in the integrated power module as
required.

(3) Check the fused ignition switch output (run/

start) fuse in the integrated power module. If OK, go
to Step 4. If not OK, repair the shorted circuit or
component as required and replace the faulty fuse.

(4) Turn the ignition switch to the On position.

Check for battery voltage at the fused ignition switch
output (run/start) fuse in the integrated power mod-
ule. If OK, go to Step 5. If not OK, repair the open
fused ignition switch output (run/start) circuit to the
ignition switch as required.

(5) Turn the ignition switch to the Off position.

Disconnect and isolate the battery negative cable.
Remove the overhead console. Check for continuity
between the ground circuit cavity of the roof wire
harness connector for the electronics module and a
good ground. There should be continuity. If OK, go to
Step 6. If not OK, repair the open ground circuit as
required.

(6) Connect the battery negative cable. Check for

battery voltage at the fused B(+) circuit cavity of the
roof wire harness connector for the electronics mod-
ule. If OK, go to Step 7. If not OK, repair the open
fused B(+) circuit to the fused B(+) fuse in the inte-
grated power module as required.

(7) Turn the ignition switch to the On position.

Check for battery voltage at the fused ignition switch
output (run/start) circuit cavity of the roof wire har-
ness connector for the electronics module. If OK,
refer to SELF-DIAGNOSTIC TEST. If not OK, repair
the open fused ignition switch output (run/start) cir-
cuit to the fuse in the integrated power module as
required.

SELF-DIAGNOSTIC TEST

A self-diagnostic test is used to determine that the

electronics module is operating properly, and that all
the PCI data bus messages are being received for ini-
tial operation. Initiate the self-diagnostic test as fol-
lows:

(1) With the ignition switch in the Off position, on

Electronic Vehicle Information Center (EVIC) and
Compass Mini-Trip Computer (CMTC) equipped vehi-
cles simultaneously depress and hold the STEP and
the RESET buttons. On Compass Temperature Mod-
ule (CT) equipped vehicles depress the C/T and the
US/M push buttons.

(2) Turn the ignition switch to the On position.
(3) Following completion of these tests, the elec-

tronics module will display one of the following mes-
sages:

8M - 2

MESSAGE SYSTEMS

OVERHEAD CONSOLE (Continued)

a. Pass Self Test (EVIC only), PASS (CT,

CMTC) - The electronics module is working properly.

b. Failed Self Test (EVIC only), FAIL (CT,

CMTC) - The electronics module has an internal fail-
ure. The electronics module is faulty and must be
replaced.

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 8 - ELECTRICAL/OVERHEAD CONSOLE -
STANDARD PROCEDURE - COMPASS VARIATION
ADJUSTMENT).

NOTE: If the compass reading display is blank and
only “CAL” appears in the display, demagnetizing
may be necessary to remove excessive residual
magnetic fields from the vehicle. (Refer to 8 - ELEC-
TRICAL/OVERHEAD CONSOLE - STANDARD PRO-
CEDURE - COMPASS DEMAGNETIZING).

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 the vehicle may
acquire during normal use. If the compass readings
appear to be erratic or out of calibration, perform the
following calibration procedure. Also, new service
replacement Electronic Modules (EVIC, CMTC, CT)
must have their compass calibrated using this proce-
dure. Do not attempt to calibrate the compass near
large metal objects such as other vehicles, large
buildings, or bridges; or, near overhead or under-
ground power lines.

NOTE: Whenever the compass is calibrated manu-
ally, the variance number must also be reset. (Refer
to 8 - ELECTRICAL/OVERHEAD CONSOLE - STAN-
DARD

PROCEDURE

COMPASS

VARIATION

ADJUSTMENT).

Calibrate the compass manually as follows:

(1) Turn the ignition switch to the On position. If

the compass/thermometer data is not currently being
displayed, momentarily depress and release the C/T
push button to reach the compass/thermometer dis-
play.

(2) On

Electronic

Vehicle

Information

Center

(EVIC) and Compass Mini-Trip Computer (CMTC)
equipped vehicles depress the Reset push button and
hold the button until “CAL” appears in the display.
This takes about ten seconds, and appears about five
seconds after “VAR = XX” is displayed. On Compass
Temperature Module (CT) equipped vehicles depress
the C/T push button and US/M push button down
until “CAL” appears in the display. This takes about
ten seconds, and appears about five seconds after
“VAR = XX” is displayed.

(3) Release the push button(s).
(4) Drive the vehicle on a level surface, away from

large metal objects and power lines, through three or
more complete circles at between five and eight kilo-
meters-per-hour (three and five miles-per-hour) for a
minimum of 48 seconds. The “CAL” message will dis-
appear from the display to indicate that the compass
is now calibrated.

NOTE: If the “CAL” 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.

COMPASS DEMAGNETIZING

A degaussing tool (Special Tool 6029) is used to

demagnetize, or degauss, the overhead console for-
ward mounting screw and the roof panel above the
overhead console. Equivalent units must be rated as
continuous duty for 110/115 volts and 60 Hz. They
must also have a field strength of over 350 gauss at 7
millimeters (0.25 inch) beyond the tip of the probe.

To demagnetize the roof panel and the overhead

console forward mounting screw, proceed as follows:

(1) Be certain that the ignition switch is in the Off

position, before you begin the demagnetizing proce-
dure.

(2) Connect the degaussing tool (Fig. 1) to an elec-

trical outlet, while keeping the tool at least 61 centi-
meters (2 feet) away from the compass unit.

(3) Slowly approach the head of the overhead con-

sole forward mounting screw with the degaussing
tool connected.

MESSAGE SYSTEMS

8M - 3

OVERHEAD CONSOLE (Continued)

(4) Contact the head of the screw with the plastic

coated tip of the degaussing tool for about two sec-
onds.

(5) With the degaussing tool still energized, slowly

back it away from the screw. When the tip of the tool
is at least 61 centimeters (2 feet) from the screw
head, disconnect the tool.

(6) Place a piece of paper approximately 22 by 28

centimeters (8.5 by 11 inches), oriented on the vehicle
lengthwise from front to rear, on the center line of
the roof at the windshield header (Fig. 2). The pur-
pose of the paper is to protect the roof panel from
scratches, and to define the area to be demagnetized.

(7) Connect the degaussing tool to an electrical

outlet, while keeping the tool at least 61 centimeters
(2 feet) away from the compass unit.

(8) Slowly approach the center line of the roof

panel at the windshield header, with the degaussing
tool connected.

(9) Contact the roof panel with the plastic coated

tip of the degaussing tool. Be sure that the template
is in place to avoid scratching the roof panel. Using a
slow, back-and-forth sweeping motion, and allowing
13 millimeters (0.50 inch) between passes, move the
tool at least 11 centimeters (4 inches) to each side of
the roof center line, and 28 centimeters (11 inches)
back from the windshield header.

(10) With the degaussing tool still energized,

slowly back it away from the roof panel. When the
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).

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 geo-

graphic location and note the zone number (Fig. 3).

(2) Turn the ignition switch to the On position. If the

compass/thermometer data is not currently being dis-
played, momentarily depress and release the C/T push
button to reach the compass/thermometer display.

(3) On

Electronic

Vehicle

Information

Center

(EVIC) and Compass Mini-Trip Computer (CMTC)
equipped vehicles depress the Reset push button and
hold the button down until “VAR = XX” appears in
the display. This takes about five seconds. On Com-
pass Temperature Module (CT) equipped vehicles
depress the C/T push button and US/M push button
down until “VAR = XX” appears in the display. This
takes about five seconds.

(4) Release the push button(s). “VAR =XX ” will

remain in the display. “XX” equals the current vari-
ance zone setting.

(5) On

Electronic

Vehicle

Information

Center

(EVIC) and Compass Mini-Trip Computer (CMTC)
equipped vehicles momentarily depress and release
the STEP button to step through the zone numbers,
until the zone number for your geographic location
appears in the display. On Compass Temperature
Module (CT) equipped vehicles depress the US/M
push button to step through the zone numbers, until
the

zone

number

for

your

geographic

location

appears in the display.

Fig. 1 DEGAUSSING TOOL 6029

Fig. 2 ROOF DEMAGNETIZING PATTERN

8M - 4

MESSAGE SYSTEMS

OVERHEAD CONSOLE (Continued)

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