Trailer Light Problem

[steve45]

I bought a trailer about 2 years ago and didn't use it (I wanted the Waverunner that came with it). Trailer had LED lights.

I tried to use the trailer last year and most of the lights didn't work. Spent a couple hours removing all the lights and cleaning their ground connections and re-wiring most of the harness. Used the trailer once.

Last month, I was going to use it again and no lights. Thought it had to be a bad ground where it plugs into the tow vehicle. (I thought the trailer hitch ball might be too dirty to provide a proper ground). I had the trailer plug ground wire attached to a screw on the trailer frame. I cleaned the connection and no dice. I drilled another hole and installed another self-tapping screw for ground and it still didn't work. I started troubleshooting the ground connection on the vehicle wiring and found 2 ohms between the plug and vehicle frame. Cleaned the connection on the vehicle frame, got the resistance down near 0 and it still didn't work.

I finally got a battery pack and tested the LEDs and they worked. After pulling my hair out, I finally figured out that the trailer was built with a replaceable tongue that slides into the frame. I guess this is so you can install a longer tongue, or replace it if you jackknife the trailer. The tongue is secured with bolts. Well, it turns out that the electrical connection between the tongue and trailer frame was bad. I ran a ground wire from the tongue to the frame and now everything works normally.

Just thought I'd throw this out there in case somebody else ever has a grounding problem that is hard to track down.

[turboman412]

I always wire all my lights with a separate ground wire. Never been a fan of grounding to the frame

[steve45]

I always wire all my lights with a separate ground wire. Never been a fan of grounding to the frame

I agree, but some lights don't have a ground wire. They ground through the mounting screw.

[nmpeter]

those sliding tongue trailers often have plastic bushing in there to help to keep the bar from seizing.

I always ran wiring from the lights all the way up front without depending on the trailer frame

[steve45]

The trailer in question is made by Featherlite.

[Gator Kev]

I always wire all my lights with a separate ground wire. Never been a fan of grounding to the frame

+1. Highly recommend running a separate ground wire. Not too difficult or expensive to run all new wires with a full ground wire. I just rewired my double Triton trailer and it wasn't hard at all even with having 9 marker lights to wire in. Just took a little planning...

I agree, but some lights don't have a ground wire. They ground through the mounting screw.

You can always connect the ground wire to the bolt for lights that use that method. All 3 sets of LED lights that I have worked with recently had a separate ground wire. One of them had the round connector attached already that you hooked onto the bolt for ground. Easy to remove the connector and connect into the ground wire.

[Gator Kev]

what kind of trailer was this on? battling an intermittent issue very similar to this one....

Just rewire it with a full ground wire. Piece of mind for the ground and brand new wires.... You can get a new wire kit at home depot for about $15. Either solder the connections if you can and use heat shrink tubing or you can buy marine connectors that you can heat shrink after crimping. I used the marine connectors and additional heat shrink tubing over top when I did mine. Both available at Home Depot or Harbor Freight (cheaper at HF). Just remove wires from the old lights and hook some twine or heavy duty fishing line to the end before you pull the old wire out through the front. That will allow you to easily pull the new wire back through the frame. You can also get a cheap fish tape from Harbor Freight, about $6 - $8, to snake through the frame if you want to reroute the wires a different way. I used both methods as I rerouted the main wires down the center and the original were down the side.

[nmpeter]

When I dicked around with trailers I often would install a cig lighter socket with 12ga wiring to run portable air compressors and cell chargers

Most trucks using electric brake controllers have that power at the bumper socket if it’s 6 pin type

[TimeBandit]

+1 on running ground wires.
Heck, never got the industry's logic with using the frame as part of a circuit .... like "wow, we sure saved a lot of copper by not running a ground wire" !!! It's just a bad idea to use the frame.... it means a whole hecavalota extra connections to fail, screws, etc.... all of which will be subject to galvanic corrosion issues, regardless of fresh or saltwater use.

Tips:
As part of my DIY trailer build a few years back, I decided to forego the a-typical trailer wiring harness (kits). Instead, I went to a Marine store and bought multi-conductor marine grade wires, for which also had enough leads for a dedicated ground. I also wired a trailer-grade sealed junction box up near the front, where I also feed-in the Hopkins big 7-prong plug.
In the few places where I "had" to splice wires.... I would twist/join the pair together, solder the twist, cover the twist with silicone, then screw-on a wire-nut also filled with silicone.
Buy good quality LED sealed (epoxy-filled) modules. These will nearly always have ground wires.
Knock on wood --- not had any lights issues since.