Auto Dim Rear mirror

I have an old style Auto Dim rear view mirror with adjustable distance from a 98 oldsmobile or cadillac. Well I wanted to know if anyone knows how to wire it to a 87 mustang. There are three wires pink, black, and dark green. Also dose anyone know were to find the backup lamp switch or wire in an 87 mustang, and  also is the door trigger a negative or a positive.

-Thanks-

P.S. sorry for all the question 

I know it's late, but.........

Door triggers are positive...I think it's BLACK/ blue at the Driver's Kick panel, but don't hold me to it...as far as the back up lamps go.....if all else fails, run a wire from the lamps in back up front...or you could look around the tranny for a harness and start testing with the DMM....MAKE SURE THE PARKING BRAKE IS ON!!!  If it's in gear, it will roll....yes it's possible even on an auto...I almost learned the hard way..thank god I was in it when it started to roll!