Trailer light problem?

[wplatehunter]

I was driving up north the other night and blew five fuses in my truck from the running lights on my boat trailer. I turned around and came home. Checked the wires, and did not find any problems. Also pulled the tail lights off, and did not see any problems. Replaced the 20amp fuse with the only fuse I had left a 15amp, and drove around town with no problems. I go to leave the next morning, and they are working for a while. Then they start to turn on and off when I would hit a bump on the Hwy, but I did not blow any fuses. The turn signals and brakes never had a problem. Whats with the running lights? I'm thinking a wire must be shorting it out some where, but I did not see any problem. Thanks

[BoxMN]

We had same problem, exact. We found it was the brown wire (running lights) using a volt meter in the plug.

From there we isolated it by unplugging one side at a time - you can do this with shorlander trailers as each side has a plug right where the trailer splits. We just unhooked one side at a time (just the brown wire) to see which side was popping fuse. Found it was the port side doing it.

Our trailer has side marker lights and the three rear lights in middle, down low. It ended up being the three light "bar" - which is on the port side brown wire - and that would be a good spot for you to look, if you haven't.

Good luck!

[wplatehunter]

Did you replace the wires or What? Thanks

[BoxMN]

So far, we just removed the light bar and put wire nuts on the ends. The corrosion was all in the light bar itself. I just have to buy one and slap it on. Gotta find a LED one, as we went LED with everything else (12 year old trailer).

[wplatehunter]

Ok thanks. Mine is a 2005 Ezloader with LED's. I will check the light.

[Jeremy airjer W]

I'd also check to see where the white wire ends up on the trailer. The white wire is the ground for the trailer. I have has a couple recently where the ground wire was bolted to the tongue of the trailer. The two beams where bolted to the tongue beam. Over time the bolts and holes rusted up and no longer completed the ground circuit to the tail lights. The solution was to run a ground wire all the way to the back of the trailer and mount it to the back of the tail lights.

[SkunkedAgain]

Every single trailer light issue that I've had was too to a bad ground somewhere. The last time, it was the bolts on the trailer tail light. They provided the ground to the trailer at the lights. I had to scrub away some of the corrosion around the bolt holes to get my lights working properly again.

[BoxMN]

Just wondering, but if it is bad ground, it won't blow fuses will it? I had bad ground on utility trailer (old rusty thing), and ended up running extra ground wire to back lights, and all fixed now. But that never blew a fuse on me, just that the lights didn't work. If it is blwing fuse it is usually a short or something (corrosion) making current flow almost stop and get hot, isn't it?

I am not electrician or trailer pro I just like to learn as much as I can from other's and my own problems, to fix it easier next time it happens to me, ha! Thanks for any more info and thoughts for troubleshooting.

[shamrock7]

Bad grounds only make people scratch their heads. They do not cause fuses to blow.

[Dave]

At least you're trying to pin down a problem with only one wire. You will have to pull the wire again and very carefully inspect it, I guess. I had one light's wire insulation that was wore down (not cut), since it rides in the trailer tube frame and must rub, and a few strands of the wire was barely visible. It must've been touching the frame when bumped at times. It especially blew the fuse faster after loading or launching since moisture was in the frame tube.

Blowing a fuse is a short. Lights blinking on and off is a bad connection.

[wallyeye]

I had a very similar problem with my shorelander trailer. I came to the conclusion that I would have to re-wire the thing. When I pulled the old wires out of the frame, low and behold there was a spot that was bare that had been causing the short and blowing the fuses.

Mine was a 1999 trailer so it isn't like it was that old either.

[wplatehunter]

Well I thought I had the problem fixed until I blew another fuse last night on the way home from the lake. This time I find some exposed wire on one of the side running lights, but it looks like it was the ground wire for the side light. Could the ground for the running lights if exposed cause it to blow a fuse? Thanks. I got a new truck, so its not the truck its in the trailer.

[pinkfloyd4ever]

I'll put this on my own stupidity- I put the wrong size bulb in my standard trailer lights, it blew out 5 fuses too. I went inch by inch on the wiring, couldnt find a nick. I put a 1157 in a 2057 (or vice versa) put the correct bulb in and no problem since. Don't know if same would be true since you have LED

[wplatehunter]

One other thing the ground is good in back and the plug to the side light is good. The exposed wire is in between the two.