Trailer brake light

[Lostbay]

Sorry if this is not the appropriate forum for trailer questions...have had years of various trailer, wiring and ground issues, but this is a new one. All lights, turn signals and brake lights on the boat trailer work when truck lights are off. When truck lights are on, one of the trailer brake lights go off when braking. All other things remain working, including that same lights turn flasher. Have checked ground on truck and ground on trailer near the hitch. Have checked all wire connections. If I'm not mistaken... if the turn signals work, with headlights on, the brake lights should as well as they pull off the same wire? Typically when I've had a ground issues in the past the turn signal on the trailer doesn't work when the brake lights won't work either. Thanks

[marine_man]

It sounds like a grounding issue to me still.

Have you checked the receptacle / pigtail coming on the pickup side with a multi-meter / test light to ensure everything on your pickup is working correctly?

If that has been done, then my next guess would be ground.

marine_man

[delmuts]

I agree, that i think it is a ground issue. Many boats trailers are grounded thru the ball hitch. Sometimes this can be iffy. The plug for my boat has a white ground wire in it. This i attached to the trailer, and ran a ground from the truck etc. into the plug.

[motley man]

Run new ground wire to lights. Over time the corrosion between bolts, frame, etc. loose ground.

[SkunkedAgain]

I had that exact same problem with an old trailer of mine. It was a bad ground. I discovered that the grounding connection at one of the trailer lights was corroded. A little sandpaper and the ground issue was fixed

[Invader440]

Bad ground on that light.