I asked the GM and Pontiac website on this and they said they couldn't help me. I swapped a 327 into my 2.8 V6 85 firebird. I ripped out the computer. My question is can I wire the rear window defogger directly to the battery alt. termanial board where I connected my fuel pump fan and MSD box to. Or do I need to reduce the volts and amps. I'm afaid that if I put the full power to the window that with the extra heat and it being cold outside it could crack the window. If I need to put a resister or reducer what size do I need? Also where can I find a simple on off timer switch? What length of time should it stay on for 1 min 2 min? Thanks for your help

 

I'm not sure about the wiring, but I'm sure it runs on 12 volts. You shouldn't need resistors or anything like that. By disconnecting the computer, you might have disturbed the power connections for the defroster somehow....but I assure you that the defroster is not controlled by the computer. You should just be able to hook it back up.

I don't know how to wire one of those timers up, but I'd imagine you could get one out of any junk car. They usually run between 5 and 10 minutes.

Older cars, especially many Japanese ones, had no timer at all. I remember my mother's '83 Accord had a simple on-off switch controlled by the ignition. The story I've heard is that running the defroster constantly shortens its life, as well as putting an extra load on the electrical system. If you can remember to turn yours off when you don't need it, just put it on a lighted toggle switch.

 

Thanks for the help. At least now i'm not worried about cracking the window. As for the computer thing in the firebird switch it had a lot of wires going to it and the camaro has very few from what I've seen. I think in the firebird the timer was in the computer and thats what the extra wires were for but I really don't know. Thats just a guess. Maybe I will get a switch from a camaro and install it in to my firebird since I have already removed my switch and put a cover plate in it. Thanks... Erik