Trailer brake light not working

[beezee28]

I have a tilt trailer that I wired with brand new wires. The light works and so does the signal lights but when I step on the brake with the running light on the light goes off. When I take my foot off the brake the lights come back on. I check the ground on both the truck and also the trailer and they are newly reset. I need help on this so that when I use the trailer at night the lights work.
Thanks in advance

 

[jenoble01]

Re: Trailer brake light not working

Check the connector at the truck with a test light just to make sure something goofy didn't happen and you have juice at the connector. Then I would check the connections for the brake light wires, sounds like a poor connection somewhere to me. You say it's a tilt trailer, possible the wire got pinched and cut, might be something worth looking at as well.

 

[Silvertip]

Re: Trailer brake light not working

Tilt trailers need a ground strap to electrically connect the pivot points. That point presents a poor ground which is very likely what's causing the problem.

 

[jtexas]

Re: Trailer brake light not working

you have a weak ground...the white wire on the trailer side needs to be bolted on tightly to a clean unpainted surface.

 

[tashasdaddy]

Re: Trailer brake light not working

end the hassle and run an independent ground from the white wire to all the fixtures, mounting nut. don't depend on the trailer frame for ground.

 

[Pony]

Re: Trailer brake light not working

I like to coat all of my grounds with petroleum jelly.

 

[Frank Acampora]

Re: Trailer brake light not working

Although I agree with the others to run a separate ground wire--I do it as a matter of course on all my trailers-- if both signal and running lights work, you do not have a ground problem. It is more likely a short since it only happens on braking. Remember signal and brake go through the same wire. Check your wiring and light fixtures again. This could happen if you crossed wires ie. put the common running light wire onto the signal wire on one fixture.

It also helps to know what type of tow vehicle you have.

 

[bruceb58]

Re: Trailer brake light not working

Duplicate post.

 

[bruceb58]

Re: Trailer brake light not working

It is not a short...that is a typical ground problem. The reason the running light is working with a bad ground is that the running light is getting a "sneak path" ground through the brake light circuit. When you apply the brakes, the sneak path is gone so the light goes out.

The sneak path is through all the nonenergized brake lights on the trailer and the vehicle that all have good grounds. The path will be through the filaments to ground. There won't be enough current to actually allow those filaments to look bright becuase the current is shared between all of them.

If you do a good job of making sure the metal is clean where you mount your lights, you don't need a ground wire.

If you run an extra ground wire and this connection at the light stud to your extra ground wire is not clean, you will have the exact problem.

 

[beezee28]

Re: Trailer brake light not working

I found the problem, I would like to thanks all you for you very helpful tip. The problem is I had a bad ground. I clean the bolt hole where the ground wire is attached and did get the brake light to work but it seems weak so I ran separated ground wire from the loghts mounting bolt to the frame and now it all works. Once again Thank You.

 

[bruceb58]

Re: Trailer brake light not working

Next time, get a dremel tool and grind down to bare metal where the nut and washer hit the trailer frame. Put the nut and washer back on and put a light coating of grease over it.