Boat trailer wiring issues - ongoing. Help!

[bzano]

I don't trailer my boat very often however this week I'm taking my boat on a camping/trailer sailing vacation to Lake George NY.
The problem I have is the lights (including the turn signals, everything) go blank after getting on the road. Last night everything went out after about a mile or two of driving. It was a short trip back to my house and it was still daylight so it was not too dangerous. As usual the power supply fuse from the battery (15 amp) to the wiring harness inside the vehicle was blown.

This problem has been ongoing for a few seasons. I retrieve the boat, upstep the mast, retract the trailer tongue(s) apply the straps and I'm ready to go. All this takes about 30 to 45 minutes. Then I plug in the lights, and everything works fine. Flawless. Then after few minutes on the road - all goes out. The next day, replace the fuse, plug in the lights, all good!

Just some additional information:

- when not in the water there is NEVER a problem. I will plug my lights in this morning and I believe everything will work fine. (once I replace the fuse)
- I have trailered a camper and car carrier recently and have no problem at all with the lights so the vehicle (V6 Dodge Durango) is not the issue.
- I replaced all the wiring and lights with LED fixtures on the trailer about 2 years ago and ran marine grade wire to wire each light for grounding instead of the using the trailer frame. I used waterproof soder/shrinking tube for connections and sealed other wire connections (three wire) with nuts and silicone.

An idea I had was perhaps the light fixtures were filling up with water (supposed to be submersible?) and once I started driving, the bouncing around moved accumulated water inside one or more of the fixtures to short out the circuit. This season I drilled holes in the bottom of each light to drain out any excess water. - Little or no change in the problem.

Any thoughts would be appreciated.

 

[rgranger]

I’ve never gone more than three seasons without some sort of trailer light problems.
All in all it is sometimes quicker to just replace the entire set.

 

[captbob47]

Harbor freight and other places sell magnetic mount trailer lights with a long cord to plug into your vehicle. Easily installed and easily removed. Mine work all the time.

 

[danooxnard]

Check all the connections for corrosion, including the light sockets, when the corrosion gets wet it heats up drawing more current, pop goes the fuse. don't put in a larger fuse to fix it. A new set of lights with new wires can save lots of time. Good luck Dano

 

[LloydB]

The concept that one 15 amp fuse blows because of a short in the recently rewired trailer should affect only the stop turn and tail lights on the trailer and not the vehicle lights is baffling. Even though it is a binary type of problem I think that you'll have to find an analog solution, at least you have apparently eliminated the need for a trailer frame ground a couple years ago.

 

[Thaniel]

As usual the power supply fuse from the battery (15 amp) to the wiring harness inside the vehicle was blown.

If the fuse blows that means there is a short to ground somewhere in the wiring. I don't believe it is water in the lights or harness etc. I would look at all the positive leads and look for a spot where the insulation is broken, chaffed or pinched and touching the ground lead or frame. Could be a short in the tail lights suppose too, since they are LED there's more to go wrong inside them.

Also more information about this 15 amp fuse might be helpful. Usually brake and tail lights are on different circuits so all the lights don't go out at the same time. Perhaps this fuse isn't to the Power supply but to some light control ECU or something?