How do I find a relay? If I walk into the local kragens/autozone is there any chance they'll know what I'm talking about? I assume it would have 3 terminals power in, power out, signal. Splice the signal wire into the reverse lights, power from the battery to the relay, to the lights. Good to go?I would suggest adding a relay (activated by the truck's reverse lights) that actually supplies the current to the trailer's reverse lights.