Left Brake Light and Turn Signal not Working on Trailer Towed by 2003 GMC Sierra
Published 07/09/2009
Question:
I have a 2003 GMC Sierra Pickup When I hook up to my boat trailer all of the lights work except the left blinker and left brake light on the trailer. My two sons own Chevy pickups can hook up to the trailer and everything works including left turn signal and brake. What are the most common problems that would cause this? Any help would be appreciated.
asked by: Jon J
Expert Reply:
I suspect that you have a blown fuse. The fuses that manage your towing circuits are located in the power distribution box located under the hood of your truck. The box sits on the inside fender on the drivers side.
Your owners manual should be able to tell you which particular fuse to look for. Once you replace the fuse, you will need to determine why the fuse blew. Carefully examine your trailer connector for corrosion or damage. Check your left turn/ brake light wiring on the trailer, looking for pinched wires or cracked or worn insulation that would allow the copper conductor to contact the trailer frame and blow the fuse.
I included a link to a trailer wiring FAQ.
