Description And Operation; Compass; Garage Door Opener Storage Bin; Reading And Courtesy Lamp - Jeep 1997 Grand Cherokee Service Manual

8V - 2 OVERHEAD CONSOLE SYSTEMS
DESCRIPTION AND OPERATION (Continued)
The push button (Step and U.S./Metric) switch
module in the overhead console is hard-wired to the
trip computer. The compass flux-gate unit is integral
to the trip computer, compass, and thermometer dis-
play module unit. Data input for all other trip com-
puter functions is received through CCD data bus
messages. The trip computer uses its internal pro-
gramming and all of these inputs to calculate and
display the requested data. If the data displayed is
incorrect, perform the
described in this group. If these tests prove inconclu-
sive, the use of a DRB scan tool and the proper Body
Diagnostic Procedures manual are recommended for
further testing of the trip computer and the CCD
data bus.
The trip computer, compass, and thermometer dis-
play module cannot be repaired, and are only avail-
able for service as a unit. If faulty, the complete
module must be replaced. The push button (Step and
U.S./Metric) switch module is serviced separately.

COMPASS

The compass will display the direction in which the
vehicle is pointed using the eight major compass
headings (Examples: north is N, northeast is NE). It
does not display the headings in actual degrees.
The self-calibrating compass unit requires no
adjusting in normal use. The only calibration that
may prove necessary is to drive the vehicle in three
complete circles, on level ground, in not less than 48
seconds. This will reorient the compass unit to its
vehicle.
The compass unit also will compensate for magne-
tism the body of the vehicle may acquire during nor-
mal 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 pro-
cession flag can exceed the compensating ability of
the compass unit if placed on the roof panel. Mag-
netic bit drivers used on the fasteners that hold the
assembly to the roof header can also affect compass
operation. If the vehicle roof should become magne-
tized, the demagnetizing and calibration procedures
found in this group may be required to restore proper
compass operation.
The compass, trip computer, and thermometer dis-
play module cannot be repaired, and are only avail-
able for service as a unit. If faulty, the complete
module must be replaced. The push button (Step and
U.S./Metric) switch module is serviced separately.

THERMOMETER

The thermometer displays the outside ambient
temperature. The temperature
changed from Fahrenheit to Celsius using the U.S./
Metric button, located just rearward of the display
self-diagnostic tests
display can
module. The displayed temperature is not an instant
reading of conditions, but an average temperature. It
may take the thermometer display several minutes
to respond to a major temperature change, such as
driving out of a heated garage into winter tempera-
tures.
When the ignition switch is turned to the Off posi-
tion, the last displayed temperature reading stays in
the thermometer unit memory. When the ignition
as switch is turned to the On position again, the ther-
mometer will display the memory temperature for
one minute; then update the display to the current
average temperature reading within five minutes.
When the outside temperature is below 3° C (37°
F), the thermometer will provide an ice indicator
function to alert the driver of possible icy road condi-
tions. The ice indicator function will cause the word
"ICE" to be flashed on the overhead console display
for approximately two minutes. The ice indicator
function will occur only one time during any ignition
switch cycle. The ice indicator function will not occur
if the display is in the elapsed time mode due to the
character limitations of the elapsed time display.
The thermometer function is supported by an
ambient temperature sensor. The sensor is mounted
outside the passenger compartment near the front
and center of the vehicle and is hard-wired to the
Body Control Module (BCM). The BCM sends a tem-
perature status message to the overhead console over
the CCD data bus network. The ambient tempera-
ture sensor is available as a separate service item.
The thermometer, compass, and trip computer dis-
play module cannot be repaired, and are only avail-
able for service as a unit. If faulty, the complete
module must be replaced. The push button (Step and
U.S./Metric) switch module and ambient temperature
sensor are serviced separately.

READING AND COURTESY LAMP

All reading and courtesy lamps located in the over-
head console are activated by the door ajar switches.
When the doors are closed, the lamps can be individ-
ually activated by depressing the corresponding lens.
When a door is open, depressing the lamp lens
switches will not turn the lamps off. Refer to Group
8L - Lamps, for diagnosis and service of the reading
and courtesy lamps.

GARAGE DOOR OPENER STORAGE BIN

A compartment in the long-type overhead console
is designed to hold most garage door opener remote
control transmitters. The transmitter is mounted
within the compartment with an adhesive-backed
be hook and loop fastener patch.
With the transmitter mounted in the storage bin,
adapter pegs located on the front of the storage bin
ZG