Issues With Replacing A Tail Light On A Boat Trailer

Updated 08/07/2025 | Published 07/09/2025

Question:

My left turn signal on boat trailer isn’t working. I bought a replacement light and the3 prong plug that goes in the back is corroded but the new harness that came with it has a single Black, red and white wire where as the original has two brown, 2 yellow and one white. How do I connect the new plug? I know two of the wires go the the little side light. I’m just trying to get lights working to get home from the lake .

asked by: Blake T

Expert Reply:

Hi Blake!

Since your original light had yellow wires, am I correct in assuming this is a drivers side light? Either way, having black, red, and white wires is definitely confusing. Odds are, the black wire be for the tail light/running light, the red wire will be for the brake light/turn signal, and the white wire will be your ground. Without knowing what light you received, I can't say 100% this will be correct, but it is the standard. The best way to know would be to put some power to the wires so you can test their functions.

If they test out the way I mentioned, you will connect both of the yellow wires to the red wire, both brown wires to the black wire, and then ground your white wire.

Let me know if this doesn't work or if the wires don't test the way I mentioned. If you could let me know which light you got, it might also help.

expert reply by: Lazer S

Lazer S.

8/7/2025

Hey Blake, How did testing the wires go? Did connecting them as suggested get your lights working so you could head home from the lake? I'm eager to hear how it turned out so I can better assist others in similar situations!