I have been trying to wire up a new stereo for my 2005 express, and I have already cut the factory harness (oops). The problem I have is that I cannot find out where the accessory wire is, and consequently the new unit will not shut off with the car because it's only wired to the 12v constant. I gave tried to use a multimeter to find the accesory wire by having the key in the on position and seeing which wire reads 12v, but the only wire I get a reading for is the 12v constant wire. Anybody know which wire is the accessory wire? Or whether there even is one?

 

Hi Sam, remember when you are looking for the signal wire that the radio will stay on until one of the doors is opened. When I first bought my van the radio would not turn off. The sensors in the door were bad and I had to replace them.

I would check the red/white wire for voltage. If it doesn't turn off when you open the doors, try another door. Both my driver and passenger door sensors were bad. The radio wouldn't turn off until I opened one of the rear doors.

This should help you identify the wire you are looking for.