Diagnosis And Testing-Compass Mini-Trip Computer: Notes

If the problem with the compass mini-trip computer module is an inaccurate or scrambled display, refer to SELF-DIAGNOSTIC TEST  below. If the problem with the compass mini-trip computer module is incorrect Vacuum Fluorescent Display (VFD) dimming levels, use a DRB scan tool and the proper Diagnostic Procedures manual to test for the correct dimming message inputs being received from the instrument cluster over the J1850 data bus. If the problem is a no-display condition, use the following procedures. For complete circuit diagrams, refer to SYSTEM WIRING DIAGRAMS (2003) or SYSTEM WIRING DIAGRAMS (2004).

1. Check the fused ignition switch output (run/start) fuse in the junction block. If OK, go to Step 2. If not OK, repair the shorted circuit or component as required and replace the faulty fuse.
2. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output (run/start) fuse in the junction block. If OK, go to Step 3. If not OK, repair the open fused ignition switch output (run/start) circuit to the ignition switch as required.
3. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Remove the overhead console. Check for continuity between the ground circuit cavities of the roof wire harness connector for the overhead console and a good ground. There should be continuity. If OK, go to Step 4. If not OK, repair the open ground circuit to ground as required.
4. Connect the battery negative cable. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output (run/start) circuit cavity of the roof wire harness connector for the overhead console. If OK, refer to SELF-DIAGNOSTIC TEST  below, for further diagnosis of the compass mini-trip computer module and the J1850 data bus. If not OK, repair the open fused ignition switch output (run/start) circuit to the junction block as required.