I just purchased a car stereo from walmart that I am putting in my boat and I need some help on it. I connected all of the speaker wires but the power wires have gotten me confused. The instructions say to connect one wire to a constant 12 volt source and the other to an ignition circuit or switched 12 volt source. Can somebody tell me how to do this because I only have 1 wire that was there before that has power. Could somebody tell me where to put the other wire?<br />Thanks