"Trailer Wiring Fault"

[Bridge4d]

I started having this same problem with my last 5er and 2014 F250. The first time was during a rain storm. After everything dried out it worked fine. Then it started happening just about every time we went out rain or shine. I tried dielectric grease, replacing the umbilical and replacing the battery with an Optimum. Replacing the battery solved the problem for a while interestingly enough...not sure why. But it came back. The Ford F-Series are known for trapping moisture in the bed plug and the trailers are known for frayed wires. I think my problem was a combination of both. The only way I was able to solve the problem was to buy a new truck and trailer.