Diagnosis And Testing - Overhead Console: Notes

If the problem with the overhead console is an inaccurate or scrambled display, refer to SELF-DIAGNOSTIC TEST  . If the problem with the overhead console is incorrect Vacuum Fluorescent Display (VFD) dimming levels, use a DRB III(R) scan tool and the proper Diagnostic Procedures manual to test for the correct dimming message inputs being received from the Body Control Module (BCM) or Front Control Module (FCM) over the J1850 Programmable Communications Interface (PCI) data bus circuit. If the problem is a no-display condition, use the following procedure. For complete circuit diagrams, refer to appropriate SYSTEM WIRING DIAGRAMS article.

1. Remove the overhead console from the headliner (Refer to REMOVAL  ).
2. Check for battery voltage at the overhead console electrical connector. Refer to appropriate SYSTEM WIRING DIAGRAMS article for connector information. If OK, go to Step 3. If not OK, Check for battery voltage at the appropriate B(+) fuse in the integrated power module, repair the open fused B(+) circuit as required.
3. Turn the ignition switch to the On position. Check the fused ignition switch output circuit(s) at the overhead console electrical connector. If OK, go to Step 4. If not OK, repair the open or shorted circuit as required.
4. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Check for continuity between the ground circuit cavity of the overhead console electrical connector and a good ground. There should be continuity. If OK, refer to SELF-DIAGNOSTIC TEST  for further diagnosis of the electronics module and the J1850 PCI data bus circuit. If not OK, repair the open ground circuit as required.