Hey Mark, Take a meter, and see if it gets 12V+ when you turn it on. If so, then this would be your power ant, or amp remote wire. AMP REMOTE if you get 12v when tuner or cd is on. PWR ANT if you only get 12V+ when the tuner is on. If you don't get any 12V+, then I have no clue what this wire is for...But you probably already know all of this. Just seeing if you checked...