Quote Originally Posted by crappiepappy View Post
Biggest problem with trailer lights is usually not being grounded good. Then comes broken wires, bared wires shorting out against the trailer, blown bulbs, blown fuses, and poor connection grounding via the trailer ball/coupler or plug prongs. I've experienced them all ... and have yet to find any short cuts to figuring out WHY the lights don't work. You may just have to work your way thru all the possible problems, until you isolate them ... then fix it to last.

... pappy
Hit the nail on the head. Grounding big issue. some use the trailer tongue and ball for grounding as some use the white wire.