I've just purchased a 1988 GTA and I have a part missing in the dashboard. I've seen pictures but I can't quite make it out. The controller is just right of the steering wheel but left of the controls for the rear defroster. It looks like a slide controller of some sort. Unfortunately the car doesn't have the owners manual so this is why I am asking. I've done a search also but no luck. Any help would be great.

Sounds like it is the audio gain slider switch.

Yea, it controls the bass level of the stock "Subs" that are located in the sail panels in the back. Heres a pic of the switch...

and the stock subs ....

they make block off plates for those, im gonna use mine for line lock or use the defroster button for it.

Thank you so very much for the replies. That darn thing was driving me crazy trying to figure it out. The factory stereo, well, any stereo is gone from the car. I'm slowly putting the pieces back together on this thing. Thanks again.