Trailor Lights?

[paceman]

About a month ago I bought a new to me boat. The trailor lights have me a bit baffled. The brake and signal lights work just fine but the running and back up lights don't work at all. I have checked the trailor fuse in the truck and it appears to be fine. Any suggestions as to where to look for the source of my problems?

[marine_man]

Can you clarify your comment about back-up lights, or are you referring to tail lights?

marine_man

[paceman]

The tail lights on the trailor don't light up when the vehicle is put in reverse.

[marine_man]

I would start with checking all the pertinent functions on the plug that comes out of your truck before attacking the trailer to make sure what you're feeding the trailer with is good.

Take a test light and verify your connector is functioning correctly. If you have a four-wire plug, brown = tail lights, yellow = left turn / brake, green = right turn / brake.

Once you have verified that is good, I'd check on your grounds. Is the white wire on the trailer side connector grounded to something on the tongue?

Are all the white wires on the back of the tail lights clean, and connected to a paint free, rust free location with some dielectric grease smeared over it?

By the way; there is a very good troubleshooting thread in the equipment forum, which I linked here:

Trailer Wiring 101

marine_man

[Eelpout08]

usually if there are no broken wires anywhere the ground wires are th culprit. if it were my trailer i would check and clean up every ground point, or better yet just rewire the whole thing, then you know what you have.

[Gadgetman]

Check the fuse box under your hood. I had the same problem, fuse in the vehicle was fine it was the fuse in the box undedr the hood that was the problem