I have searched TGO and the Internet at large for information regarding the dashboard light gremlins my car has. I have found some good information and have torn my dashboard apart, but have not been able to fix the problem. I am in desperate need of assistance here...

91 RS 3.1L

When the parking/headlights are turned on, all instrument backlighting with the exception of the speedo go out as does the gear selector, radio and AC controls. The volt meter and temp gauges pin out. The oil gauge does not work anyway. The fuel gauge does still operate (it's just hard to see with no backlighting. Additionally, the switch for the rear window defogger was making this loud buzzing/vibrating noise.

So far I have cleaned the grounds for the headlights as well as the one on the radiator support. I also checked the continuity of the engine to firewall ground. The G200 ground under the dash is fine and the connectors to the back of the cluster have continuity to G200. I disconnected the harness going to the tail light assemblies to eliminate a bad ground back there. I have also removed the cluster and cannot see any obvious breaks in the flexible circuit board. I did poke around the board with a meter and did not find any breaks.

The problem disappears every once in a while for a couple of minutes and then it comes right back without any prompting. If the door is open and the headlight switch is set for the interior lights on, the gauges all work normally. As soon as I close the door (or depress the door switch) everything malufunctions again.

I have also tried replacing the headlight switch to no avail.

BTW, what is the white transistor just above the audible alarm in the convenience center for?

Thank you for taking the time to help me through this frustrating time.

 

Well, after ripping apart the dash without finding anything definitive, it had kind of started working again. At least the problem is intermittent now, but it is still there and I can't figure out where else to look.

I also noticed that the radio is not picking up FM at all (stock radio) and the AM is spotty at best. I know the radio shares it's ground with all the other lights and gauges I have been having issues with, but the G200 ground itself is clean and shiny. Is it possible that the radio could be shorted internally?

Anyone have any suggestions for a very frustrated third gen owner from NY?