Overhead Console Systems - Jeep 1996 Grand Cherokee Service Manual

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GENERAL INFORMATION
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . 1
DESCRIPTION AND OPERATION
COMPASS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
GARAGE DOOR OPENER STORAGE BIN . . . . . . 2
READING/COURTESY LAMPS . . . . . . . . . . . . . . 2
SUNGLASSES STORAGE BIN . . . . . . . . . . . . . . . 2
THERMOMETER . . . . . . . . . . . . . . . . . . . . . . . . . 2
TRIP COMPUTER . . . . . . . . . . . . . . . . . . . . . . . . 1
DIAGNOSIS AND TESTING
THERMOMETER . . . . . . . . . . . . . . . . . . . . . . . . . 3
TRIP COMPUTER/COMPASS/DISPLAY
GENERAL INFORMATION
INTRODUCTION
Two overhead consoles featuring a mini trip com-
puter, an electronic compass, and a thermometer are
available factory-installed options on this model. A
long version of the overhead console is used on mod-
els without a power sunroof option. A short version of
the overhead console is used on models with a power
sunroof option.
The long overhead console includes two front-
mounted and two rear-mounted reading/courtesy
lamps, a garage door opener storage bin, and a sun-
glasses storage bin. The short overhead console
includes two reading courtesy lamps and houses the
power sunroof switch.
Following are general descriptions of the major
components used in the overhead console. Refer to
8W-49 Overhead Console in Group 8W - Wiring Dia-
grams for complete circuit descriptions and diagrams.
DESCRIPTION AND OPERATION
TRIP COMPUTER
A mini trip computer is available on this model to
provide several electrical functions and features. The
trip computer contains a central processing unit and
interfaces with other modules in the vehicle on the
Chrysler Collision Detection (CCD) data bus network.
The CCD data bus network allows the sharing of
sensor information. This helps to reduce wiring har-
ness complexity, reduce internal controller hardware,
and reduce component sensor current loads. At the

OVERHEAD CONSOLE SYSTEMS

CONTENTS
page
OVERHEAD CONSOLE SYSTEMS
MODULE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
SERVICE PROCEDURES
COMPASS CALIBRATION . . . . . . . . . . . . . . . . . . 4
COMPASS DEMAGNETIZING . . . . . . . . . . . . . . . 5
COMPASS VARIATION ADJUSTMENT . . . . . . . . 4
REMOVAL AND INSTALLATION
AMBIENT TEMPERATURE SENSOR . . . . . . . . . . 7
OVERHEAD CONSOLE . . . . . . . . . . . . . . . . . . . . 6
PUSH-BUTTON MODULE . . . . . . . . . . . . . . . . . . 7
READING/COURTESY LAMP BULBS . . . . . . . . . 7
TRIP COMPUTER, COMPASS,
THERMOMETER, DISPLAY MODULE . . . . . . . 6
same time, this system provides increased reliability,
enhanced diagnostics, and allows the addition of
many new feature capabilities.
Some of the functions and features that the trip
computer supports and/or controls, include the fol-
lowing displays:
• Compass/temperature
• Trip odometer (ODO)
• Average miles per gallon (AVG ECO)
• Instant miles per gallon (ECO)
• Distance to empty (DTE)
• Elapsed time (ET)
• Blank display.
Momentarily depressing and releasing the Step
button when the ignition switch is in the On position
will cause the overhead console display to step
sequentially through the listed display options.
Momentarily depressing and releasing the U.S/Metric
button toggles the display between U.S. and Metric
measurements. For more information on the trip
computer features refer to the owner's manual in the
vehicle glove box.
The push button module is hard-wired to the trip
computer. The compass flux-gate unit is integral to
the trip computer, compass, thermometer, display
module unit. Data input for all other trip computer
functions is received through CCD data bus network
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 is recommended for
8V - 1
page
self-diagnostic tests as