Right Brake Light Quits Working When Hooked To Race Car Trailer.

Question:

this is a 1995 freightliner fl70 , it was used to pull a horse trailer, I bought it to pull race car trailer but the right brake light wont work on the truck or trailer. brake light works on truck but not when its hooked to trailer. everything else works great even the left brake light. hooked another truck to trailer, works great. Would appreciate some tips as to what to look for. right turn signal works when hooked to trailer or not

asked by: Billy P

Expert Reply:

I would start the troubleshooting by inspecting the tail light connection to ground. It should be without paint or corrosion. You should also check out the tail light bracket connection to the trailer frame. If the bracket is bolted to the trailer frame there may be rust and corrosion inhibiting the ground connection.

Finally, check to make sure the actual connectors on both the truck and trailer are clean and free of corrosion. A bad ground or dirty connections are the two most common causes of lights not functioning properly. I have included a couple of videos below on troubleshooting the ground wire that should help.

expert reply by: Patrick R