on my 89 GTA when i turn on the park lamps the headlamps come up but not on. i have replace the headlamp switch inside, but they still come up. anyone know anything about this. thanks mark

 

There's a 6x6" square box on your firewall between the brake booster and the distributor that controls the headlight doors. You can pretty much bank on that module being faulty. When they go bad the headlight doors do all kinds of exorcist ****. When mine went bad in 99, I picked up a new one from the dealer for about $120. I'd hate to think what they cost now, if they're still available.

The module changed at least once during the thirdgen production run. What you'll probably want to do is try a spare, if you have a spare laying around or that you can try without spending $120. Otherwise see if you can get scans of the 1989 Firebird service manual. There are a couple charts of diagnostics you can run before you go through trying to find a potentially expensive replacement module.

 

thanks, i picked one up at my freinds salvage yard today for almost nothing, still have to try it. i called the dealer and retail is around $260.00 ouch. i will keep you posted. thanks mark