trailer running light problems

[dakotashooter2]

Last fall I converted 2 trailers to LED running lights. here is my problem.... I can't get the running lights to light on either trailer. Flasher, blinkers and break lights work fine. The lights are 2 different brands which reduces the chance of a faulty light and on 2 different trailer kind of eliminates the chance of bad wires on the trailer. The standard light systems worked fine on both before changing over. I have hooked them up to 2 different trucks both (Dakotas) with factory wiring, with the same results. I am still suspicious that this may be a Dodge problem because If I hook the lights directly to a battery they light up just fine. Anyone else have this issue ?

[deadeye762]

sounds to me that its a ground problem. Especially since it works on other trucks and batteries.

Usually when they all go out, its ground related.
I would check the ground wire on the receptacle as well as where the ground wire connects to the vehicle.

Once you have ensured that the ground is solid, I would take a test light and go on the trailer side of the plug and start tracking where the current ends. I would be surprised if it wasnt ground though being it works on other trucks.

[dakotashooter2]

I am also suspicious of the ground but why is it OK with standard lights but not with the LEDs? I hooked the truck up to a 3rd trailer with standard lights and they lit up fine. Think I'm gonna hook up to my dads Chevy and see if things work. I did have issues with a Dodge many years ago and it turned out to be a ground issue in an aftermarket harness. But if its the ground on the truck how come it works for reg but not LED and if its the trailer how come it works when hooked direct to a battery?

[deadeye762]

if your hooking up to the battery then you have a direct ground there (the neg terminal) when using the truck, you are using the ground from the harness which more than likely is somewhere close to the plug harness

[Theduckguru]

90% of the time it will be your lights are not properly grounded.

[dakotashooter2]

Yup ground problem. I've noticed that with modern plastic housed lights (and other things) simple grounding to the frame (close to the connector) is no longer adequate unless the ground is made very close to the fixture. I ran a ground from the connector, the length of the trailers back to the lights and they work.

[deadeye762]

good deal!!

glad you got them working!

[dakotashooter2]

Here is what I finally figured out. On most of the trailers I have the shaft for the hitch is bolted not welded to the trailer. As rust eventually forms between the shaft and trailer the ground is lost. I now run a bonding wire on all such trailers and the problem is solved.