Brake light problem on HF trailer

[LDK]

I'm stumped on this one, my left brake light won't work but the left turn signal does. It's a standard 4 pin plug in and I checked the tow vehicle with a tester and everything seems OK there. I know alot of people would think it's the ground but I'm not so sure. When I wired the trailer I soldered all the connections and taped them with electrical tape. I used dielectric grease on the grounded wire. The light bulb is a double filament bulb. I even switch bulbs from the other side with the same results. When the running lights are off, the left brake light will work but not as bright as the other side. When the running lights are on, no brake light at all on the left side but the turn signal will work. I'm thinking it might be a bad light fixture. Any comments.

[High Desert]

As long as your sure on all the grounds I'd say either a bad fixture may be possible. You're sure the running and brake light wires are correct into the light, yes? As the brake and turn are on the same wire, it effects which side of the element lights up. Could account for the brake light being dimmer on that side.

[LDK]

I did some more tinkering and found out it was a faulty ground. I'll have to ground it from the light fixture to the frame now. Live and learn I guess.

[High Desert]

I did some more tinkering and found out it was a faulty ground. I'll have to ground it from the light fixture to the frame now. Live and learn I guess.

I have a lot of practice dealing with trailers of all sizes. General rule is that 90% of the time it is ground problems lol. The other 10% is broken wires, burned out bulbs and bad connector plugs. Glad you found the problem

[Shadow Catcher]

Best bet forget grounding to the frame and run a ground wire.

[LDK]

Best bet forget grounding to the frame and run a ground wire.

Imma gonna do the other light fixtures the same way now!

[absolutsnwbrdr]

I had major grounding issues on my HF trailer. Problem was that I couldnt get a consistent ground between from piece to piece... the red paint was preventing it. I ended up running a ground wire the entire way around the trailer.

[Cliffmeister2000]

Grounding to the frame is fine, as long as you run a ground wire too!

[Dale M.]

Ironically ground is ground.... Whether its a complete welded frame or ground wire, it will function correctly.... The problem is all mechanical, and paint makes a real good insulator... If its a bolt together frame, run a ground wire because you will be forever chasing a poor bolt through electrical connection.... IF its a fully welded frame just be sure all grounds for lamps sockets have a clean (bright steel) connecting point and you use a solid mechanical connection with a good dielectric grease to protect mechanical connection from corrosion...

If you have lamps mounted on wood or fiberglass panels and are using a frame as ground conductor, be sure to extend ground form frame to fixture...

Dale

[LDK]

I ended up grounding each light fixture to the frame. Even though I welded my frame, it still doesn't ground very good. I also used dielectric grease on those grounding points too.

[LDK]

If I have any more issues with the ground, I'll run a single ground wire to all the fixtures. Hopefully I won't have any more problems.

[Larwyn]

A copper ground to each fixture is always a good idea.