I have a 1997 Buick Park Ave with no dash lights or tail lights. Checked all fuse boxes and no blown fuses, replaced headlight switch (used) no help, replaced the Lamp Control module (used) worked for a day then back to square one. Is there a way to test the LCM? is there another system tied in that would cause this? any help greatly appreciated.

When you had no dash lights, did your radio and HVAC control head light up? Did the dimmer control work at all?

When the lamp control module was replaced, the dash lights AND tail lights worked?

The radio clock would light up as well as the temp indicator by the heater controls but none of the buttons had lights, also the shift indicator and the odometer were lit up. after I replaced the LCM everything worked but only until I got home and put the car in park and they went out and have yet to come back on. Went and got another LCM (used) to see if it helps. Checked all the bulbs and fuses in all the fuse boxes all were good look for a chaff in a wire in the trunk all looks good also checked under fuse box in the engine compartment to see if mice got up under and chewed anything. Ill post an update if the 2nd LCM works

Update: As of now its fixed! put in the 2nd LCM still no lights, started to think it was something to do with the twilight sentinel, started looking up on the dash for a sensor that'* when I noticed the sensor by the mirror. Looking at the plug it looked undone and it was. Pushed it in to seat it and the lights came on! Could have saved $30 but I guess that'* how it goes and if you think about it that'* cheap experience.

Hey, you found it! 30 bucks is a lot less if any garage had to diagnose an electrical problem.....I have seen guys get buried in electrical work...

A lot of Techs, especially GM Techs miss this......I pick on GM Techs, because I was one......as any GM will tell you, there is a specific path you take when diagnosing a "concern"(there are no problems)......and one of the first things is, "a visual inspection".....many guys make their jobs harder, by forgetting this simple step.