Roadmaster diodes seem to be commonly used for this on this site. I have a few sitting around for future projects...My apologies...I probably wasn't super clear. I know there are wires already going to the aux buttons and I know where they are at. As I previously stated, my lights are already hooked up to the trailer hitch wiring harness to come on when I put it in reverse. I want to be able to additionally turn them on by using the aux buttons...do I just run a wire to the factory installed wires that's already run for the aux buttons?