Just in case anyone needs this for a 1997 Expy. This is the wire to tap into, inside the cab, for your Navigation/Stereo head unit camera reverse sense wire. The wire goes from ground to 12v. when the vehicle is put into reverse and back to ground in drive. There was another Black/Pink wire under the dash below steering column that goes from 12v. to ground, not the one you want.
I added a switch to the dash so I could have it work normal or, while driving, be able to flip the switch and look at the trailer connection.
I added a switch to the dash so I could have it work normal or, while driving, be able to flip the switch and look at the trailer connection.
