Stuck in Park

O/P what kind (led or incandescent) and how many lights are on your trailer(s). It may be that the brake light circuit is simply overloaded and the fuse is protecting as it should or the switch is burning out due to overload.. Does it have a factory tow package? Is this a boat trailer, used in salt water? If so, I'd be looking at corroded taillights and grounds. What is the rating on the fuse? As an aside, I was shocked to see how small the wiring was to the 12V ports in the dash. I don't thing these trucks are over wired by any means. They are just enough for stock use in most cases.

 

Both trailers have the standard basic lights from Walmart. One standard non-LED bulb on each side. The trailer wiring was done years ago by a trailer hitch shop. They are both utility trailers, and have never been in any water other than the rain. Sorry, but I don't have any idea about the fuse. And this setup has worked great for over 7 years.