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  1. 1. ZJ OVERHEAD CONSOLE 8C - 1 OVERHEAD CONSOLE CONTENTS page pageDIAGNOSIS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 SERVICE PROCEDURES . . . . . . . . . . . . . . . . . . . 8GENERAL INFORMATION . . . . . . . . . . . . . . . . . . 1 SPECIFICATIONS . . . . . . . . . . . . . . . . . . . . . . . . 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 COMPUTER In 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 position display is turned on or off using the COMP/TEMPwill cause the overhead console display to step se- button to the left of the display.quentially through the various display options. Input The self-calibrating compass unit requires no ad-for the trip computer functions is received on the justing in normal use. The only calibration that mayCCD bus lines. If the data displayed is wrong, run prove necessary is to drive the vehicle in 3 completeself-diagnostics before replacing the computer. The circles, on level ground, in not less than 48 seconds.DRB scan tool is recommended for checking the CCD This will reorient the unit to its vehicle.bus lines. The unit also will compensate for magnetism the body of the vehicle may acquire during normal use.COMPASS However, avoid placing anything magnetic directly on The compass will display the direction in which the the roof of the vehicle. Magnetic mounts for an an-vehicle is pointed using the eight major compass tenna, a repair order hat or a funeral procession flagheadings (Examples: north is N, northeast is NE). It can exceed the compensating ability of the compassdoes not display the headings in actual degrees. The unit if placed on the roof panel. Magnetic bit drivers
  2. 2. 8C - 2 OVERHEAD CONSOLE ZJused on the fasteners that hold the assembly to the When all doors and the liftgate are closed, the lampsroof header can also affect compass operation. can be individually activated by depressing the corre- If the front console attaching screw is re- sponding lens. When a door and/or the liftgate isplaced, the new screw must be a #10 stainless open, depressing the lamp lens switches will not turnsteel. the lamps off. Refer to Group 8L - Lamps, for diag- If the vehicle roof should become magnetized, the nosis and service of these lamps.demagnetizing and calibration procedures may be re-quired to restore proper operation. KEYLESS ENTRY RECEIVER The long overhead console houses the keyless entryTHERMOMETER receiver. Refer to Group 8P - Power Locks, for diag- The thermometer displays the outside ambient nosis and service of this component.temperature. The temperature displayed can bechanged from Fahrenheit to Celsius using the US/ REMOTE GARAGE DOOR OPENER STORAGEMETRIC button. The displayed temperature is not A compartment in the long overhead console is de-an instant reading of conditions, but an average tem-perature. It may take the unit several minutes to re- signed to hold most remote garage door opener trans-act to a major temperature change such as driving mitters. The transmitter is mounted within theout of a heated garage into winter temperatures. compartment with an adhesive-backed hook and loop When the ignition switch is turned OFF, the last fastener patch. Then one or two pegs are selecteddisplayed temperature reading stays in memory. and mounted on a post on the inside of the storageWhen the ignition switch is turned ON again, the compartment door. The pegs may be stacked, if nec-thermometer will display the memory temperature essary. The peg(s) selected must be long enough tofor one minute; then update the display to the cur- activate the button of the transmitter each time therent average temperature reading within five min- storage compartment door is depressed.utes. When the vehicle is equipped with ATC, ambient SUNGLASSES STORAGEtemperature data is obtained from the HEVAC mod- A flocked storage compartment for sunglasses is in-ule on the CCD bus lines. On vehicles without ATC, cluded in the long overhead console. This compart-the ambient temperature sensor is hard-wired to the ment features a push/push-type latch and a viscoustrip computer. dampening system for a fluid opening motion.READING AND COURTESY LAMPS All reading and courtesy lamps in the overheadconsole are activated by the door jamb switches. DIAGNOSIS Follow the appropriate diagnostic flow chart: (1) With the ignition switch in the OFF position,• Chart 1 - Describes the procedures for compass simultaneously press and hold the STEP button andand display problems. the US/METRIC button.• Chart 2 - Describes the procedures for outside (2) Turn ignition switch to the ON position.temperature measuring problems. (3) Continue to hold both buttons until the display• Chart 3 - Describes the procedures for illumination performs a walking segment test. In this test all oflamp problems. the compass points are displayed, along with various number combinations. The test will:TRIP COMPUTER/COMPASS/DISPLAY SELF- (a) Verify that all display segments are func-DIAGNOSTIC TEST tional. (b) Check internal circuitry. This self-diagnostic test is used to determine that (c) Check that all CCD bus messages needed arethe trip computer/compass and all of its display seg- being received.ments are operating properly electrically. It also is If tests (a) and (b) are passed, the module will au-used to verify that all CCD bus messages required tomatically return to normal operation at completionare being properly received. Initiate the self-diagnos- of tests. If any segment should fail to light duringtic test as follows: test (a), the unit is faulty and requires replacement. If test (b) fails, the display will read FAIL. If test (c)
  3. 3. ZJ OVERHEAD CONSOLE 8C - 3fails, 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
  4. 4. 8C - 4 OVERHEAD CONSOLE ZJ Chart 1 (Continued)
  5. 5. ZJ OVERHEAD CONSOLE 8C - 5 Chart 2
  6. 6. 8C - 6 OVERHEAD CONSOLE ZJ Chart 3
  7. 7. ZJ OVERHEAD CONSOLE 8C - 7THERMOMETER DIAGNOSIS cuit is shorted. If the temperature is below -40°C When the vehicle is equipped with ATC, ambient (-40°F) or an open circuit exists, the system will dis-temperature data is obtained from the HEVAC mod- play OC (open circuit).ule on the CCD bus lines. On vehicles without ATC, To diagnose the temperature sensor, perform thethe ambient temperature sensor is hard-wired to the following procedures.trip computer. (1) Turn the ignition switch to OFF. Unplug sensor The thermometer function is supported by a tem- connector. (2) Measure resistance of sensor. At -40°F the re-perature sensor, a wiring circuit and a portion of the sistance is 336K ohms. At 140°F the resistance isoverhead console display. The sensor is mounted to 2.488K ohms. Sensor resistance should read betweenthe center of the radiator support behind the grille these two values. If OK, go to Trip Computer/Com-(Fig. 1). pass/Display Self-Diagnostic Test. If not OK, replace the sensor. Fig. 1 Temperature Sensor. 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- Fig. 2 Overhead Console Harness Connector
  8. 8. 8C - 8 OVERHEAD CONSOLE ZJ SERVICE PROCEDURESCOMPASS VARIATION ADJUSTMENT ity of the compass. DO NOT use magnetic tools Variance is the difference between magnetic north when servicing the overhead console.and geographic north. In some areas, the differencebetween magnetic and geographic north is great The compass features a self-calibrating design,enough to cause the compass to give false readings. If which simplifies the calibration procedure. This fea-this occurs, the variance must be set. ture automatically updates the compass calibration To set the variance: while the vehicle is being driven. This takes into ac- (1) Using the map in Fig. 3, find your geographic count small changes in residual magnetism the vehi-location and note the zone number. cle may acquire during normal use. Do not attempt to calibrate the compass near large metal objects such as other vehicles, large buildings or bridges. Whenever the compass is calibrated manually, the variation number must also be reset. See Variation 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 takes about 10 seconds and appears about 5 seconds after VAR is displayed. (3) Release both buttons. (4) Drive vehicle on a level surface that is away from large metal objects through 3 or more complete circles in not less than 48 seconds. The CAL message will disappear to indicate that the compass is now calibrated. If CAL message remains in display, either there is excessive magnetism near the compass or the unit is faulty. Repeat the demagnetizing and calibration procedures at least one more time. If the wrong direction is still indicated, the area selected may be too close to a strong mag- netic field. Repeat the calibration procedure in another location. COMPASS DEMAGNETIZING Fig. 3 Variance Settings The tool used to degauss or demagnetize the for- (2) Turn ignition switch to the ON position. ward console attaching screw and roof panel is the (3) Depress both the US/METRIC and STEP but- Miller Tool 6029. Equivalent units must be rated astons. Hold down until VAR is displayed. This takes continuous duty for 110/115 volts and 60Hz. Theyabout 5 seconds. must also have a field strength of over 350 gauss at (4) Release both buttons. 1/4-inch beyond the tip of the probe. (5) Press the US/METRIC button to step through The degaussing tool is used to demagnetize boththe numbers until the zone number for your area ap- the roof panel and the console forward mountingpears in the display. screw, as follows: (6) Press the STEP button to enter this zone num- (1) Be sure the ignition switch is in the OFF posi-ber into compass unit memory. tion before you begin the demagnetizing procedure. (7) Confirm correct directions are indicated. (2) Plug in the degaussing tool, while keeping the tool at least 2 feet away from the compass unit.COMPASS CALIBRATION (3) Slowly approach the head of the forward mounting screw with the plastic coated tip of the de-CAUTION: DO NOT place any external magnets gaussing tool. Contact the head of the screw forsuch as magnetic roof mount antennas, in the vicin- about 2 seconds.
  9. 9. ZJ OVERHEAD CONSOLE 8C - 9 (4) With the degaussing tool still energized, slowly AMBIENT TEMPERATURE SENSOR REMOVE/back it away from the screw until the tool is at least INSTALL2 feet from the screw head, then unplug the tool. (1) Remove the radiator grille (Fig. 5). (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. Fig. 5 Radiator Grille Remove/Install (2) Disconnect sensor wiring connector (Fig. 6). Fig. 4 Roof Demagnetizing Pattern Fig. 6 Ambient Temperature Sensor Remove/Install (6) Plug in the degaussing tool, while keeping thetool at least 2 feet away from the compass unit. (3) Remove sensor mounting bolt and remove sen- (7) Slowly approach the center line of the roof sor.panel at the windshield header with the degaussing (4) Reverse removal procedures to install.tool plugged in. (8) Contact the roof panel with the tip of the tool. OVERHEAD CONSOLE REMOVE/INSTALLBe sure template is in place to avoid scratching the LONG STYLEroof panel. Using a slow, back and forth sweeping (1) Remove console forward mounting screw (Fig.motion and allowing 1/2-inch between passes (Fig. 4), 7).move the tool at least 4 inches either side of the roof (2) Slide console forward until the console detachescenter line and 11 inches back from the windshield from the rear mounting bracket.header. (3) Disconnect wire harnesses from keyless entry (9) With the degaussing tool still energized, slowly receiver and trip computer (Fig. 8).back it away from the roof panel until the tip is at (4) Reverse removal procedures to install.least 2 feet from the roof. Then unplug the tool. (10) Calibrate the compass and adjust variance as SHORT STYLEdescribed in this group. (1) Remove console forward mounting screw (Fig. 9).
  10. 10. 8C - 10 OVERHEAD CONSOLE ZJ Fig. 7 Long Overhead Console Remove/Install Fig. 9 Short Overhead Console Remove/Install Fig. 8 Keyless Entry Harness Connector (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. Fig. 10 Trip Computer Remove/InstallTRIP COMPUTER REMOVE/INSTALL PUSH-BUTTON MODULE REMOVE/INSTALL (1) Remove overhead console and disconnect wir- (1) Remove overhead console and disconnect wir-ing. See Overhead Console Remove/Install. ing. See Overhead Console Remove/Install. (2) Unplug harness connector from trip computer. (2) Unplug harness connectors from push-button (3) Remove 2 screws holding trip computer to con- module.sole (Fig. 10). (3) Remove 4 screws holding module to console (4) Spread retaining tabs on the sides to remove (Fig. 10).trip computer from the console. (4) Remove module from console. (5) Reverse removal procedures to install. (5) Reverse removal procedures to install.
  11. 11. ZJ OVERHEAD CONSOLE 8C - 11READING/COURTESY LAMP BULB REMOVE/ (3) Install new bulb by pushing firmly into socket.INSTALL (4) Pivot lens up into position and snap in. Test by (1) Insert a long flat-bladed tool at the notch on pressing lens for proper operation and lighting.the curved edge of the lens. Carefully pry the lensfrom the housing and pivot the lens down. It may be KEYLESS ENTRY RECEIVERnecessary to move the tool along the edge to free the Refer to Group 8P - Power Locks for service of thislens. component. (2) Remove bulb by pulling straight down. SPECIFICATIONS TRIP COMPUTER FUEL SENDER CALIBRATION