I agree 100% about tinned wire. I bought 2 strand 14 ga tinned wire from West Marine right off the spool. Got about 50' of it and made my own harness. Bought two LED lights and it has works great the last several years. I got to agree with everyone that a lot of the problems are associated with the ground. I think if I were to do it again, I would just get 3 strand and run an independent ground to the lights rather than grounding them to the trailer. But either way, get tinned wire, it last so much longer than the non tinned crap they sell for trailer harnesses.