Locating and Repairing Poor Ground Connection Causing Turn Signals to Flash Together

Question:

after hooking all the wiring to the lights and running a ground wire to trailer. I pluged it to a factory plug ford 150 2002.they all work .But one turn light works the other make both work.Do i have a bad ground.

asked by: paul T

Expert Reply:

As you suspected, you have a poor ground connection at some point.

It is important to have a continuous ground connection from the tow vehicle, to the trailer and continuing on to the trailer lights. The trailer connector on your F150 needs to be grounded to clean metal. The connector on the trailer will be grounded to the trailer frame, usually on the trailer tongue. Make sure this connection is clean and free of corrosion. The trailer lights will receive their ground connection either by the mounting studs being in direct metal to metal contact with the trailer frame, or via a separate ground wire connected directly to the trailer frame. Make sure that the point where the lamp mounting studs or ground wires attach to the frame are secure and not corroded. A plastic license plate bracket sandwiched in between the lamp and trailer frame can disrupt the ground connection. Running a short jumper wire from the mounting stud to the trailer frame can retain the ground connection.

If this is a trailer with a tilting bed, using a short jumper wire to connect the bed and the trailer frame will ensure a continuous ground connection between the two portions of the trailer.

expert reply by: Mike L