Trailer Lights blow a fuse

[IT Guy]

Here is a fun one.

Launched the boat yesterday (didn't unplug the lights), burned some gas and then put the boat back on the trailer with the lights unplugged. Hooked up the lights and they all worked. 10 minutes down the road I lost the running lights and blow a fuse in the truck. Blinkers, brakes and brake lights still work. This is the second time in a row this has happened. All worked fine the first 10 time I got the boat wet.

New truck, new boat & new trailer. I am hesitant to unplug the lights because I lose the trailer brakes and it is a heavy boat on a steep ramp.

Any ideas?

[BobT]

A blown fuse is a good indicator that you have a short-circuit somewhere. Perhaps when the trailer is submerged, dirt is washed off and then when you are driving the wires vibrate into contact with the trailer frame.

Bob

[Tofishem]

I've had that same problem with my truck/trailer, blown fuses (twice) when not unplugging the light and backing into water. Ever since I started unplugging the lights before backing into the water that problem has stopped.

[IT Guy]

I just hate to unplug because I have had some issues with the boat dragging the truck down the ramp. I need the trailer brakes.

Just wondering if there were any other solutions out there.

[Chris Haley]

You have a short. It will be easy to find however. It will be either right by one of the lights, or where the wires come out of the frame. You have to check all the small running lights on the frame also. I just had this problem with a friends boat, and it turned out to be a rubbed wire on one of the small side running lights.

[IT Guy]

I checked all the visible wires and nothing appears to be a problem. If it is a short it is buried within the frame of the trailer. Bummer

[Jeremy airjer W]

Two questions. 1. Have you checked to see if the fuse blows with the trailer disconnected? 2. I assume that when everything "dries out" the fuse doesn't blow? I think before I condemed the trailer wiring I would pull all the running light bulbs out of the sockets and then check to see if the fuse blows. if it does than I would agree that something has gone bad with the harness, If not than we can focus on the light sockets/assemblies.

Its to bad you didn't post before Friday. I was in Elk River all weekend for a batch party and would have been more than happy to take a look at it for ya!

[Guest]

If all else fails, switch over to LED lights on the trailer.. way less current draw.

Check your ground wires at the lights, the tongue, and on the truck.. make sure you have good clean connection everywhere. I had a weak ground for a while and it contributed to blown fuses. I would have never noticed it if I didnt see a spark in the darkness where my ground wire connects to the trailer by the tongue... the grounding surface was dirty and there was a poor connection. A circuit will heat up if there is not a solid connection and there are constant power surges.

[dirtking]

I've had the problem of running lights not working - the fuse was blow under my hood on the drivers side - 2001 f-150 - the chevys have a fuse box under their hoods too - try that?

[IT Guy]

I will let it go for a couple of days without the trailer hooked up to see if that pops the fuse. Most of the running light wires are not accessible except for those on the fenders. All ground connections I can see are good and clean.