i have a 9815...it is not ipod compatible so to say but the kca-420i will work with it, because my ex had it in his car and now i have the head unit and a difference kca-420i. aux is on...everything is hooked up. is that anyway to test if there is power coming out of the interface box without shorting anything? i got it off ebay so maybe its bad>??? anyway to check for sure