Please bare with me here, you will quickly see that I know just enough on this subject to be dangerous. I'm trying to switch two audio signals on and off into one Aux audio input of my motorcycles stereo system. I have a Satellite Radio that I want to hear most of the time. I also have a GPS that when I'm fellowing a route, at times will give voice directions. both of these signals will be going into the same Aux input of the stereo. I need a way to switch from the Satellite radio to the GPS when a signal from the GPS is received. will a simple relay do the job? there isn't much voltage coming from the GPS to the speakers to use as a signal for switching. I put a volt meter across the speaker wires and as best as I can tell there is less than a volt there. please try to condescend down to my level in your response that I might understand how this can be done. thank you for your help and your patience.