Cluster Illumination Diagnosis
The diagnosis found here addresses an inoperative instrument cluster illumination lamp condition. If the problem being diagnosed is a single inoperative illumination lamp, be certain that the bulb and bulb holder unit are properly installed in the instrument cluster electronic circuit board. If no installation problems are found replace the faulty bulb and bulb holder unit.
If all of the cluster illumination lamps are inoperative and the problem being diagnosed includes inoperative exterior lighting controlled by the headlamp switch, that system needs to be repaired first. (Refer to LAMPS/LIGHTING-EXTERIOR ). If no exterior lighting system problems are found, the following procedure will help locate a short or open in the cluster illumination lamp circuit. If the problem being diagnosed involves a lack of dimming control for the odometer/trip odometer or gear selector indicator Vacuum Fluorescent Display (VFD) units, but all of the other cluster illumination lamps can be dimmed, test and repair the headlamp switch output circuit between the instrument cluster and the headlamp switch as required.
Refer to the appropriate wiring information. The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.
- Check the instrument panel dimmer fuse (Fuse 9-5 ampere) in the Junction Block (JB). If OK, go to Step 2. If not OK, repair the shorted circuit or component as required and replace the faulty fuse.
- Turn the exterior lamps On with the headlamp switch. Rotate the headlamp switch panel lamps dimmer thumbwheel upward to just before the interior lamps detent. Check for battery voltage at the instrument panel dimmer fuse (Fuse 9-5 ampere) in the JB. Rotate the panel lamps dimmer thumbwheel downward while observing the test voltmeter. The reading should go from battery voltage to zero volts. If OK, go to Step 3. If not OK, repair the open panel lamps dimmer switch signal circuit between the headlamp switch and the JB as required.
- Turn the exterior lamps Off. Disconnect and isolate the battery negative cable. Remove the instrument cluster. Remove the instrument panel dimmer fuse (Fuse 9-5 ampere) from the JB. Probe the panel lamps driver circuit cavity of the instrument panel wire harness connector (Connector C2) for the instrument cluster. Check for continuity to a good ground. There should be no continuity. If OK, go to Step 4. If not OK, repair the shorted panel lamps driver circuit between the instrument cluster and the JB as required.
- Reinstall the instrument panel dimmer fuse (Fuse 9-5 ampere) in the JB. Reconnect the battery negative cable. Turn the exterior lamps On with the headlamp switch. Rotate the headlamp switch panel lamps dimmer thumbwheel upward to just before the interior lamps detent. Check for battery voltage at the panel lamps driver circuit cavity of the instrument panel wire harness connector (Connector C2) for the instrument cluster. If OK, replace the faulty bulb and bulb holder units. If not OK, repair the open panel lamps driver circuit between the instrument cluster and the JB as required.