Need help here fellow Fm'rs. The fuse on my truck keep blowing up everytime i hook the boat trailer. I check for shorts (open wires) and i cant fine any. All the trailers lights works (tail, brake, turn) except when i plug the trailer and after few minutes of driving the tail lights fuse blows.. and i end up with no trailer lights.. It only blow when the trailer lights are hitch up..

i would check the plug on the trailer side first as you indicate in issues when not connected. make sure you dont have a wire that has slipped and is touching another or grounding out. if everything is cool there then the fun part comes. start tracing the harness in the frame if possible to find a point where it has become damaged, pinched or broken. you might check the lights themselves to make sure nothing is broken or grounded in them. corrosion will cause shorts too. good luck

It might be your vehicle wiring too. If the wiring isn't robust enough to allow all the current being pulled by your trailer, it will heat up and blow your fuse. Dodge vehicles are notorious for this.

Another thing you could check if you have a tester is, na dthis happend to me. When I bought my last truck it didn't have a hitch on it for some reason so I had the dealership put one on, and do the wiring, when the bone heads did it they hooked the ground wire to the hot ground for the truck. On your vehicles you have 2 grounds, one is hot and one is not. Take our tester and put it in the hole that is for the ground wire to your vehicle and if the light comes on, that is your problem.

My Dad’s truck/trailer had the exact same issue. We played around and fixed what we thought was the short several times, but it still kept happening. We started thinking it might be the truck, so we hooked it up to a different vehicle and the same thing happened. If there was something wrong with the wires, we couldn’t find it, so we were thinking it might have been the hookup. To save ourselves any more trouble we just re-did the whole thing, and now it works great. I wish I could tell ya it was easier than that, and it probly could have been if weren’t so electrically challenged, but we were tired of the hassle. Probly went through about 30+ fuses during the whole ordeal!

sounds like you have an intermittant problem.
Have you checked for water in the light fixtures?
Another thing to follow the wires from the connector to the lights and visually look for wires that have worn through the insulation. This would be caused by vibration.

thank you guys for all the tips. could not exactly point where the short was, but i ended up splicing the wires where the swing tongue because the wires in that area was bent, but did not see any open wires, but it did fix the problem.. Now i can go fishing at sunrise and fish after sunset...