Running Lights on Trailer Will Not Function When Brakes are Applied
Question:
I have a 4 wire flat connector on the 2003 Silverado and a 5 wire on the trailer. Eveything operates fine, turn signals, running lights. When I press on the breaks the running lights go off. release the brake and they come back on. If the running lghts arent on, the break lights works. Can you help?
asked by: gordon g
Expert Reply:
I would be happy to help you with that. What you are describing is the classic description of an insufficient ground connection. When the running lights are on, the trailer is drawing maximum amperage because all lights are being used. If there is a ground problem, this is when it will manifest itself.
Make sure that the trailers ground lead that is coming off of the trailer connector is securely grounded to rust free, clean metal. This connection is typically made on the trailer tongue. Each individual lamp is usually grounded by its connection to the trailer frame. Make sure that the point where each lamp attaches to the trailer frame is also free of corrosion.
The 4 wire flat connector on the rear of your Silverado should also have a ground connection to the truck frame, check this connection as well.
I have attached a link to the right that has many trailer wiring troubleshooting techniques that you may find helpful also.
