UHaul Running Lights Out/Fuse Blows on TV

[Kevin A]

OK, I know the answer to this probably involves some plain old detective sleuthing, but here goes...

While driving home from Florida, our running lights on the trailer suddenly quit working. I discovered that they are wired through the harness to the license plate light on our VW Eurovan and the fuse was blown. I tried a new fuse and blew it again. Then I put in a larger fuse and the TV license plate light stays on but more dimly and the trailer running lights still do not work. The TV license plate light works fine when the trailer is unhooked.

So... I'm assuming that I have a short somewhere in the trailer or wiring harness of the trailer. Right? When we get home I'll take the bed down and open up the area under the rear seats to see if any connections came loose. Everything looks OK on the outside, but it could be a bad plug, too. Ah, the fun of old trailers!

[Frederick L. Simson]

Originally Posted by Kevin A

I'm assuming that I have a short somewhere in the trailer or wiring harness of the trailer. Right?

Yes, I think you're on the right path. Look inside the Tail Light/Marker Light fixtures themselves first before taking the bed apart. I had a Back-up light crimp connection fail inside the fixture last year which fried the rivet and plastic socket mount right out. I smelled mine before I saw it. Had to replace the whole fixture, which was only 5 years old.

[mary and bob]

I had an odd occurrence with tail & marker lights blowing the tow vehicle fuse. I was suspecting that there was a short in the trailer wiring, but it turned out to be a bad tail light bulb that shorted out internally. Sometimes it is necessary to isolate circuits to find the problem, as in cut wires .

[Greybeard]

One way to begin is by unplugging the TV and using an ohm meter or some continuity measuring device, look for a ground at the trailer plug end of the wiring connector on the lead going to the marker lights. It may be a high resistance ground if the lights work dimly with a larger fuse.
If you can see a ground, them pull the bulbs one at a time to see if one of them removes the ground when it is removed from a socket.
If the ground remains. then it may be a corroded socket. Take a look at them all and clean the contacts going back to see when/if the ground disappears.
If the ground remains, then it may be time to remove the wires one at a time, going back to the connector to see if/when the ground is removed.
If it is possible to follow the wiring, it may be possible to remove wires following a logical way from the plug to the lights.

Another way is to remove the bulbs in the trailer and reconnect the TV with a fuse in and see if it blows. If it does, then it is likely wiring, not a bulb.
Basically it is a process of starting at one end and trying not to go off on a tangent trying a variety of possibilites without and plan or logic.
Hopes this helps.
Richard

[Roger Kimble]

Water will make a short also

[Kevin A]

OK, I had the chance to check out my light and water problems yesterday since it was so mild in Oak Park. The running lights were out because of a wire that had frayed on the tongue. This was an earlier repair and I must have done it poorly, since the wires became exposed, rusted, and pulled apart. I cleaned the ends, reattached, and carefully covered the connection. It should be fine now.

The water leak in the trailer was a loose hose connection under the kitchen sink faucet. I snugged up the hose connector and it seems to be holding tight now. This may be a replacement fix next summer if the connection doesn't hold tight. I'm guessing the travel vibrations loosened it.

Thanks for all the suggestions. Both fixes turned out to be easy and the first things I checked. I guess I should have had a clue on the wiring that if I had fixed it earlier, it probably was the culprit!