1995 buick roadmaster rear defrost loc.

I'm installing a r/s keyless into this vehicle and was wondering if anyone knew where the rear defrost wire location was and if I would need a relay for it. Some people have told me that some cars need relays and some dont. Thanks.

Hey, another fellow Roadmaster owner here! I have a '96 Estate, with automatic climate controls. (Models with manual climate controls might be different.) I haven't tried to hook up the defroster in my car yet, but I'm inside of it right now. When I push the defrost button on the climate control panel, I can hear a relay clicking in the passenger-side kick panel. I would guess that there's a low-current signal crom the backside of the climate control panel, which then goes over to the factory relay, and is then high-current to the back of the car. Time to either remove the kick panel, or the climate control head, and start testing all the wires.