# Problem with trailer lights



## Workdawg (Apr 17, 2010)

I just put new lights and wiring on my trailer and everything works fine until I start the truck. Everything works ok then except the brake lights.They will not come on. They work if the truck is not running but will not if it is running. Anyone have an idea as to what to do to correct this. Thanks....Wayne :?:


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## perchin (Apr 17, 2010)

I'd make sure your ground is good. 99% of lighting problems are grounding issues. If it is a tilt trailer put a ground up front and run a jumper from the front ground to each light also.


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## Workdawg (Apr 17, 2010)

Thanks Perchin...I'll give that a try..I thought it was grounded ok, but I will check it tomarrow.


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## Pruitt1222 (Apr 18, 2010)

What kind of truck are you towing with? Sounds to me like it has nothing to do with your wiring job and more with the tow rig. Does it have a factory tow wiring harness, plug and play, or hard wired?


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## perchin (Apr 18, 2010)

Hmmmmm...... I guess time will tell. Is it a tilt trailer?, my last tilt trailer had the 100% same issue to a tee......... It was the grounding NOT the rig. Example::: Have you ever hooked up to a camper that has not been pulled in a while? Well they are usually grounded through the ball coupler, resulting in poor and weak lights for about the first couple of miles untill the rust is gone on the inside of the coupler and off of the ball.


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## Truckmechanic (Apr 18, 2010)

Pruitt1222 said:


> What kind of truck are you towing with? Sounds to me like it has nothing to do with your wiring job and more with the tow rig. Does it have a factory tow wiring harness, plug and play, or hard wired?




I was thinking maybe the truck as wel with them working with ignition off. What type of plug, 4 pin or 7 ?


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## Workdawg (Apr 18, 2010)

1. Truck is a 2000 Chevy S-10
2. Trailer is a tilt trailer.
3. Plug is a 4 pin. not factory installed.


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## Pruitt1222 (Apr 18, 2010)

It could be a poor ground, Do you know if your brake and turn signals use the same bulb?


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## perchin (Apr 18, 2010)

I guess if it were me I wouldn't want to be tearing apart a bunch of crap to only find out it was a grounding issue. I would simply run a temperary jumper from the existing ground up front to the tail-lights first to see what then happens. If that was not the issue, well then I would go tearing into the trucks wiring.


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## Workdawg (Apr 18, 2010)

Thanks for all the help guys.. The problem was the ground on the truck...got that fixed and everything works fine..


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## Pruitt1222 (Apr 18, 2010)

Glad you got it taken care of, I thought it may have been a ground issue but would have never placed my chips on it. I had the same problem outof my wifes truck and it was wired wrong, it needed a 5wire to 4 wire converter on it and it did the exact same thing. Glad it was a easy fix and glad I aint a betting man.


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## perchin (Apr 18, 2010)

Workdawg said:


> Thanks for all the help guys.. The problem was the ground on the truck...got that fixed and everything works fine..



Tis' almost always a ground issue. Glad you got er up and going, now get out there are reel in the big ones. 8)


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