I use the nine volt battery to test for what wire goes to what speaker. Start by having the wire stripped back on wires you expect are speaker wires. Next pick a wire you think may be positive and hold it on the (+) of the nine volt battery. It's the male side, and test each other wire until you hear it click. If you can see the speaker, which I realize won't always be true, and it moves up or out then you have a correct speaker set. Write side its on weather its front or rear and the color codes with + and - written. I like to knot that pair. Use a test light to decide which is your memory wire and which is you power wire.