Added Running Lights to Trailer But they Will Not Light Up

Question:

I wanted to add running lights to my trailer I have 3 in the back and 3 on each side. The lights I bought have only one wire coming out so I hooked the tail light wire directly to this light and it doesnt come on. I have power all the way to the light socket with my volt meter. All my lights work fine except the ones I want to add, they wont come on.

asked by: Josh

Expert Reply:

There could be a couple of issues here. The more lights you add, the more power they draw. If the combined amperage draw of the lights exceeds the amperage rating of the vehicle side wiring system then either some lights will not light up or you could blow a fuse on the vehicle side. The solution is to switch everything over to LED lights which draw only a fraction of the power of incandescent lights.

The other possible issue is a bad ground. You mentioned the lights you want to add have one wire. This means that they likely ground through the mounting hardware. A good ground will attach to a clean, bare metal and corrosion free surface using steel hardware. If the trailer is aluminum then running a jumper ground from the light to the main trailer connector could help.

expert reply by: Michael H