reviving an old thread. I want to do the same and wire the stereo to an extra switch to keep it on and not have it cut out every time i turn the engine off. From the picture that the op posted of the back of the ignition switch, which wire is it that goes to the back of the head unit for power? (sorry i'm not much of an electrician and don't have a volt meter). I would want to cut this wire ( or take it out of the back of the plug) and then connect it to the wire that comes from the extra switch which would be the white wire in the 2nd picture. Is that correct?