OVERHEAD CONSOLE

CONTENTS

page page

DIAGNOSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1

SERVICE PROCEDURES . . . . . . . . . . . . . . . . . . . 8SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . 11

GENERAL INFORMATION

Two overhead consoles featuring an electronic com-pass, thermometer, and a trip computer are availableoptions for Grand Cherokee models. A long version ofthe overhead console is used in models without apower sunroof option. The long overhead console in-cludes four reading/courtesy lamps (2 front and 2rear), a remote garage door opener storage compart-ment, a sunglasses storage compartment, and housesthe remote keyless entry receiver.

A short version of the overhead console is used inmodels with a power sunroof option. The short over-head console includes two reading courtesy lampsand houses the power sunroof switch. Following aregeneral descriptions of major components used in theoverhead console. Refer to Group 8W - Wiring Dia-grams for complete circuit descriptions and diagrams.

TRIP COMPUTERIn addition to the thermometer/compass function,

the overhead console display can be switched to thefollowing trip computer readouts:• 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 STEPbutton when the ignition switch is in the ON positionwill cause the overhead console display to step se-quentially through the various display options. Inputfor the trip computer functions is received on theCCD bus lines. If the data displayed is wrong, runself-diagnostics before replacing the computer. TheDRB scan tool is recommended for checking the CCDbus lines.

COMPASSThe compass will display the direction in which the

vehicle is pointed using the eight major compassheadings (Examples: north is N, northeast is NE). Itdoes not display the headings in actual degrees. The

display is turned on or off using the COMP/TEMPbutton to the left of the display.

The self-calibrating compass unit requires no ad-justing in normal use. The only calibration that mayprove necessary is to drive the vehicle in 3 completecircles, on level ground, in not less than 48 seconds.This will reorient the unit to its vehicle.

The unit also will compensate for magnetism thebody of the vehicle may acquire during normal use.However, avoid placing anything magnetic directly onthe roof of the vehicle. Magnetic mounts for an an-tenna, a repair order hat or a funeral procession flagcan exceed the compensating ability of the compassunit if placed on the roof panel. Magnetic bit drivers

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used on the fasteners that hold the assembly to theroof header can also affect compass operation.

If the front console attaching screw is re-placed, the new screw must be a #10 stainlesssteel.

If the vehicle roof should become magnetized, thedemagnetizing and calibration procedures may be re-quired to restore proper operation.

THERMOMETERThe thermometer displays the outside ambient

temperature. The temperature displayed can bechanged from Fahrenheit to Celsius using the US/METRIC button. The displayed temperature is notan instant reading of conditions, but an average tem-perature. It may take the unit several minutes to re-act to a major temperature change such as drivingout of a heated garage into winter temperatures.

When the ignition switch is turned OFF, the lastdisplayed temperature reading stays in memory.When the ignition switch is turned ON again, thethermometer will display the memory temperaturefor one minute; then update the display to the cur-rent average temperature reading within five min-utes.

When the vehicle is equipped with ATC, ambienttemperature data is obtained from the HEVAC mod-ule on the CCD bus lines. On vehicles without ATC,the ambient temperature sensor is hard-wired to thetrip computer.

READING AND COURTESY LAMPSAll reading and courtesy lamps in the overhead

console are activated by the door jamb switches.

When all doors and the liftgate are closed, the lampscan be individually activated by depressing the corre-sponding lens. When a door and/or the liftgate isopen, depressing the lamp lens switches will not turnthe lamps off. Refer to Group 8L - Lamps, for diag-nosis and service of these lamps.

KEYLESS ENTRY RECEIVERThe long overhead console houses the keyless entry

receiver. Refer to Group 8P - Power Locks, for diag-nosis and service of this component.

REMOTE GARAGE DOOR OPENER STORAGEA compartment in the long overhead console is de-

signed to hold most remote garage door opener trans-mitters. The transmitter is mounted within thecompartment with an adhesive-backed hook and loopfastener patch. Then one or two pegs are selectedand mounted on a post on the inside of the storagecompartment door. The pegs may be stacked, if nec-essary. The peg(s) selected must be long enough toactivate the button of the transmitter each time thestorage compartment door is depressed.

SUNGLASSES STORAGEA flocked storage compartment for sunglasses is in-

cluded in the long overhead console. This compart-ment features a push/push-type latch and a viscousdampening system for a fluid opening motion.

DIAGNOSIS

Follow the appropriate diagnostic flow chart:• Chart 1 - Describes the procedures for compassand display problems.• Chart 2 - Describes the procedures for outsidetemperature measuring problems.• Chart 3 - Describes the procedures for illuminationlamp problems.

TRIP COMPUTER/COMPASS/DISPLAY SELF-DIAGNOSTIC TEST

This self-diagnostic test is used to determine thatthe trip computer/compass and all of its display seg-ments are operating properly electrically. It also isused to verify that all CCD bus messages requiredare being properly received. Initiate the self-diagnos-tic test as follows:

(1) With the ignition switch in the OFF position,simultaneously press and hold the STEP button andthe US/METRIC button.

(2) Turn ignition switch to the ON position.(3) Continue to hold both buttons until the display

performs a walking segment test. In this test all ofthe compass points are displayed, along with variousnumber combinations. The test will:

(a) Verify that all display segments are func-tional.

(b) Check internal circuitry.(c) Check that all CCD bus messages needed are

being received.If tests (a) and (b) are passed, the module will au-

tomatically return to normal operation at completionof tests. If any segment should fail to light duringtest (a), the unit is faulty and requires replacement.If test (b) fails, the display will read FAIL. If test (c)

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fails, the display will read CCD. Momentarily pressand release either button to exit the self-diagnosticmode.

If the compass functions, but accuracy is sus-pect, it may be necessary to perform a variationadjustment. This procedure allows the unit toaccommodate variations in the earth’s mag-netic field strength based on geographic loca-tion. See Compass Variation Adjustment, in thisgroup.

If the compass display has blanked out andonly CAL appears, demagnetizing may be nec-essary to remove excessive residual magneticfields from the vehicle. See Compass Demagne-tizing, in this group.

Chart 1

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Chart 1 (Continued)

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Chart 2

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Chart 3

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THERMOMETER DIAGNOSISWhen the vehicle is equipped with ATC, ambient

temperature data is obtained from the HEVAC mod-ule on the CCD bus lines. On vehicles without ATC,the ambient temperature sensor is hard-wired to thetrip computer.

The thermometer function is supported by a tem-perature sensor, a wiring circuit and a portion of theoverhead console display. The sensor is mounted tothe center of the radiator support behind the grille(Fig. 1).

If any portion of the circuit fails, it will self-diag-nose as an open or short circuit. The system will dis-play SC (short circuit) when the sensor is exposed totemperatures in excess of 55°C (131°F) or if the cir-

cuit is shorted. If the temperature is below -40°C(-40°F) or an open circuit exists, the system will dis-play OC (open circuit).

To diagnose the temperature sensor, perform thefollowing procedures.

(1) Turn the ignition switch to OFF. Unplug sensorconnector.

(2) Measure resistance of sensor. At -40°F the re-sistance is 336K ohms. At 140°F the resistance is2.488K ohms. Sensor resistance should read betweenthese two values. If OK, go to Trip Computer/Com-pass/Display Self-Diagnostic Test. If not OK, replacethe sensor.

Fig. 1 Temperature Sensor.

Fig. 2 Overhead Console Harness Connector

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SERVICE PROCEDURES

COMPASS VARIATION ADJUSTMENTVariance is the difference between magnetic north

and geographic north. In some areas, the differencebetween magnetic and geographic north is greatenough to cause the compass to give false readings. Ifthis occurs, the variance must be set.

To set the variance:(1) Using the map in Fig. 3, find your geographic

location and note the zone number.

(2) Turn ignition switch to the ON position.(3) Depress both the US/METRIC and STEP but-

tons. Hold down until VAR is displayed. This takesabout 5 seconds.

(4) Release both buttons.(5) Press the US/METRIC button to step through

the numbers until the zone number for your area ap-pears in the display.

(6) Press the STEP button to enter this zone num-ber into compass unit memory.

(7) Confirm correct directions are indicated.

COMPASS CALIBRATION

CAUTION: DO NOT place any external magnetssuch as magnetic roof mount antennas, in the vicin-

ity of the compass. DO NOT use magnetic toolswhen servicing the overhead console.

The compass features a self-calibrating design,which simplifies the calibration procedure. This fea-ture automatically updates the compass calibrationwhile the vehicle is being driven. This takes into ac-count small changes in residual magnetism the vehi-cle may acquire during normal use. Do not attemptto calibrate the compass near large metal objectssuch as other vehicles, large buildings or bridges.

Whenever the compass is calibrated manually,the variation number must also be reset. SeeVariation Adjustment Procedure, in this group.

Calibrate the compass manually as follows:(1) Start the engine.(2) Depress both the US/METRIC and STEP but-

tons. Hold down until CAL is displayed. This takesabout 10 seconds and appears about 5 seconds afterVAR is displayed.

(3) Release both buttons.(4) Drive vehicle on a level surface that is away

from large metal objects through 3 or more completecircles in not less than 48 seconds. The CAL messagewill disappear to indicate that the compass is nowcalibrated.

If CAL message remains in display, eitherthere is excessive magnetism near the compassor the unit is faulty. Repeat the demagnetizingand calibration procedures at least one moretime.

If the wrong direction is still indicated, thearea selected may be too close to a strong mag-netic field. Repeat the calibration procedure inanother location.

COMPASS DEMAGNETIZINGThe tool used to degauss or demagnetize the for-

ward console attaching screw and roof panel is theMiller Tool 6029. Equivalent units must be rated ascontinuous duty for 110/115 volts and 60Hz. Theymust also have a field strength of over 350 gauss at1/4-inch beyond the tip of the probe.

The degaussing tool is used to demagnetize boththe roof panel and the console forward mountingscrew, as follows:

(1) Be sure the ignition switch is in the OFF posi-tion before you begin the demagnetizing procedure.

(2) Plug in the degaussing tool, while keeping thetool at least 2 feet away from the compass unit.

(3) Slowly approach the head of the forwardmounting screw with the plastic coated tip of the de-gaussing tool. Contact the head of the screw forabout 2 seconds.

Fig. 3 Variance Settings

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(4) With the degaussing tool still energized, slowlyback it away from the screw until the tool is at least2 feet from the screw head, then unplug the tool.

(5) Place an 8-1/2 X 11 inch piece of paper, orientedlengthwise from front to rear, on the center line ofthe roof at the windshield header (Fig. 4). The pur-pose of the paper is to protect the roof panel fromscratches and define the area to be demagnetized.

(6) Plug in the degaussing tool, while keeping thetool at least 2 feet away from the compass unit.

(7) Slowly approach the center line of the roofpanel at the windshield header with the degaussingtool plugged in.

(8) Contact the roof panel with the tip of the tool.Be sure template is in place to avoid scratching theroof panel. Using a slow, back and forth sweepingmotion and allowing 1/2-inch between passes (Fig. 4),move the tool at least 4 inches either side of the roofcenter line and 11 inches back from the windshieldheader.

(9) With the degaussing tool still energized, slowlyback it away from the roof panel until the tip is atleast 2 feet from the roof. Then unplug the tool.

(10) Calibrate the compass and adjust variance asdescribed in this group.

AMBIENT TEMPERATURE SENSOR REMOVE/INSTALL

(1) Remove the radiator grille (Fig. 5).

(2) Disconnect sensor wiring connector (Fig. 6).

(3) Remove sensor mounting bolt and remove sen-sor.

(4) Reverse removal procedures to install.

OVERHEAD CONSOLE REMOVE/INSTALL

LONG STYLE(1) Remove console forward mounting screw (Fig.

7).(2) Slide console forward until the console detaches

from the rear mounting bracket.(3) Disconnect wire harnesses from keyless entry

receiver and trip computer (Fig. 8).(4) Reverse removal procedures to install.

SHORT STYLE(1) Remove console forward mounting screw (Fig.

9).

Fig. 4 Roof Demagnetizing Pattern

Fig. 5 Radiator Grille Remove/Install

Fig. 6 Ambient Temperature Sensor Remove/Install

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(2) Gently pry downwards at rear of console to re-lease 2 snap clips.

(3) Disconnect wire harnesses from trip computerand power sunroof switch.

(4) Reverse removal procedures to install.

TRIP COMPUTER REMOVE/INSTALL(1) Remove overhead console and disconnect wir-

ing. See Overhead Console Remove/Install.(2) Unplug harness connector from trip computer.(3) Remove 2 screws holding trip computer to con-

sole (Fig. 10).(4) Spread retaining tabs on the sides to remove

trip computer from the console.(5) Reverse removal procedures to install.

PUSH-BUTTON MODULE REMOVE/INSTALL(1) Remove overhead console and disconnect wir-

ing. See Overhead Console Remove/Install.(2) Unplug harness connectors from push-button

module.(3) Remove 4 screws holding module to console

(Fig. 10).(4) Remove module from console.(5) Reverse removal procedures to install.

Fig. 7 Long Overhead Console Remove/Install

Fig. 8 Keyless Entry Harness Connector

Fig. 9 Short Overhead Console Remove/Install

Fig. 10 Trip Computer Remove/Install

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READING/COURTESY LAMP BULB REMOVE/INSTALL

(1) Insert a long flat-bladed tool at the notch onthe curved edge of the lens. Carefully pry the lensfrom the housing and pivot the lens down. It may benecessary to move the tool along the edge to free thelens.

(2) Remove bulb by pulling straight down.

(3) Install new bulb by pushing firmly into socket.(4) Pivot lens up into position and snap in. Test by

pressing lens for proper operation and lighting.

KEYLESS ENTRY RECEIVERRefer to Group 8P - Power Locks for service of this

component.

SPECIFICATIONS

TRIP COMPUTER FUEL SENDERCALIBRATION

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