Diagnosing and Repairing Ground Problem on Trailer Being Towed by 1998 GMC Jimmy
Question:
I rewired my trailer with a new light kit and installed a new 4 flat connector to the vehicles wiring package. When I turn on the left signal, BOTH signals on the trailer flash. When I turn on the right signal, NEITHER signal on the trailer flashes. Also, the license plate lights on the vehicle flash with the trailer lights. Is this a grounding issue? If so, where do I start?
asked by: Dean
Expert Reply:
You are correct, this is a ground problem. Starting with your Jimmy, make sure that the white lead on 4-flat trailer connector you installed is grounded to clean metal on the chassis. If the mounting point has any corrosion, it will prevent a good connection. The same holds true for the ground wire coming off of the trailer connector on the trailer. The white wire coming from the trailer connector needs to be securely grounded to clean metal on the trailer frame. One other place to check is the mounting points for each of the lamps on the trailer. They receive their ground connection from their physical attachment to the trailer frame. If these connection points are not tight or if they are corroded, you will not get good ground continuity which would certainly cause the problems you describe.
