i have searched on here and i could not find what i was looking for. what i want to do is have a reverse light turn on when i shift into reverse, but i cant find a wire that has 12 volts ONLY when its in reverse. if i could find that, i could hook a relay to it and wire the light. anyone know where such a wire is on a 550? there is a single wire and plug on the right side, that when i take it off, the reverse light on the dash comes on. is this the wire i need to use?