Question:
I only have 2 wires to each light, each light has 3 wires. Now what?
asked by: Henry
Expert Reply:
It sounds like you just purchased trailer tail lights like the Optronics # TLL9RK. These have 3 wires; one for the running/tail lights, one for the turn signal (for each side), and then one for the ground.
Your old set of lights likely grounded through their mounting hardware so all you need to do is secure the ground wire to a clean, bare-metal surface on the frame of your trailer and your new lights should work properly.
LED Combination Tail Light Kit for Trailers under 80" Wide - Submersible - Driver and Passenger
