I've been posting in Audio to try to figure this out too. My '88 GTA didn't have any radio or anything in it and the previous owner had used sidecutters to remove his "system". I've installed a new head unit and have nice sound, but it'd be interesting to see if the factory amp still works. I need the wiring diagram and can't find anything in any of my resource material. Does anyone know how this thing is supposed to work?

thanks guys