Right Brake Light Out On Trailer - Works when lights are on

[LionBear]

My right brake light is out on my boat trailer. When my lights are on, it works fine - turn signal and everything.

When my lights are off the right brake light and turn signal do not work. I can dig into electrical a little, but I'm no pro. What do you think? How can I fix this?

 

[Evinbuck]

Re: Right Brake Light Out On Trailer - Works when lights are on

Trailer light problems the largest percentage of the time comes down to a grounding problem. That is always the best place to begin. The ground wire is typically white and will be grounded to a bolt or screw somewhere on the trailer frame. Make sure it is cleaned and tight. Then go to the light causing problems and assure where it is bolted that it is clean and tight. Assure the brass and solder connection on the bulb is clean as well as the socket it is in. Assure the wires going into the light are not broken, loose or corroded. Trailer lights are always getting dunked in water and wherever there is a connection you can be sure it's gonna get wet. Unlike your car/truck those lights may get moisture but not soaked so maintenance on corrosion is pretty much the norm with boat trailers. This is the basics so there can be other problems beyond this advice.

 

[Captain Caveman]

Re: Right Brake Light Out On Trailer - Works when lights are on

I had old trailer lights once where the brake/turn lights would only work when I kept my truck lights off. It was a grounding issue and Evinbuck is right on with his advice. Many light assemblies are grounded via the bolt and nut that holds them to the trailer. Make sure that there isn't rust accumulation there. If you've checked out everything in the list above, you may need to pull the wire through the trailer (attach string or new wire at the far end) and inspect the wire that runs through the trailer. If there is a bend or kink somewhere along the line where the wire's insulation got scrapped away, you could have bare power wires touching the metal frame.

 

[LionBear]

Re: Right Brake Light Out On Trailer - Works when lights are on

I had old trailer lights once where the brake/turn lights would only work when I kept my truck lights off. It was a grounding issue and Evinbuck is right on with his advice. Many light assemblies are grounded via the bolt and nut that holds them to the trailer. Make sure that there isn't rust accumulation there. If you've checked out everything in the list above, you may need to pull the wire through the trailer (attach string or new wire at the far end) and inspect the wire that runs through the trailer. If there is a bend or kink somewhere along the line where the wire's insulation got scrapped away, you could have bare power wires touching the metal frame.

That's some good advice. This will be my starting point. Thanks!