Does anyone know where I can locate a new heater mode control motor for a 1985 GSl-SE or someone who rebuild the motor? I've seen a few salvage but hate to do all the labor to get old one out and put a new one in and have it fail.

 

Then why did you buy a 26 year old car?

Seriously, salvage is your easiest/cheapest option. I can't speak for your item in particular, but it may be possible to locate a new one somewhere, try Mazdatrix, and expect it to be expensive.