problem with trailer lights

Hi guys

I have a problem with my driver side lights on my trailer (ifor williams 510). The passenger side lights work but there is an intermittent fault with the driver side ones.

Does anybody have any ideas what couold be wrong or where to start looking?

Start looking in the wiring - likely a short or other flaw in the wiring for that side of the trailer. The fact that they work interminttently would suggest to me that the fault is such that the wires are sometimes in good contact and at others lose that contact, which is not uncommon. That said, unless you are experienced with this your best bet is to seek the assistance of a professional who can correctly locate and correct the issue.

First, clean the contacts between the truck and trailer. A pencil eraser works great.
Then, check the contacts inside each of the jacks (plugs). If that doesn't fix the issue, you have to follow each of the wires in the harness to locate the short.
I would find all the grommets where wires pass through and see if one is worn.
Essentially, you have a wire shorting somewhere.
When I have that issue, I check contacts, grounds, connections, and pass through points.

The problem could lie in you vechiel to check with a trailer board or another trailer.
Main problems dirty /green contacts in plug-socket.
Water in plug socket.
Wire corosion in plug.
Wire been bitten or snagged.
Bad earth.
Junction box with water in corosion /green wires.
Lamp holders coroded bad earth and posative.
Cable frayed broken cores exposed.
This is some probable causes.

If your near hertford england I could sort out the problem were are you if in england.

This is an ongoing problem for me. What I've done is to pick up a set of ~$20.00 magnetic tow lights and hook them to a 12 volt battery in the rear tack room. They are always on while I drive, which is never a problem. My trailer is dark and harder to see at night. I've had my truck's connectors checked and my trailer wiring thoroughly gone over, but the problem continues to recur. I'm reading this thread, too. =/

In my experience, bad ground(s) are often the cause, e.g. The connection between the socket and the trailer.
Posted via Mobile Device

Some times its a simple thing like that and others you have to get the tester out and avo meter in some cases and check out the wireing.
I have just done my barn owners trailer I put new red white leds on the wings (fenders) and 2 small red marker lights on the side at the rear as to aid reverceing through gate ways in the dark so you can put the back of the trailer were you want it.
A compleat service of the rear lights was done and corosion was found and cleaned off.
I also installed 2 twin 8watt flouresent lights so if loading in the dark the trailer is nice and bright inside and inviteing.