Trailer Brake Lights Not Functional, But Turn Signals Work
Question:
I have a 7-way connector on GMC 3500 going to a trailer equipped with a 4-way flat connector. Problem is I get L and R turn signals ok, tail lights ok, but only left stop light, no Right stop light. I have checked bulbs and filaments are good. I even tried new bulbs.
asked by: Stacey
Expert Reply:
Is your 7-way factory installed with the tow package, or was it installed aftermarket with a taillight converter? If this is an OEM tow package, the directional and brake lights are combined on the same circuit, if one is not working neither will the other.
If you are using an aftermarket taillight converter feeding into your 7-way, you will want to troubleshoot it. Trace the wiring back from the connector and locate the converter box. You will want to use a circuit tester such as part # PTW2993 and test the red brake wire entering the box. If you are getting a signal on that wire as the brakes are pressed, but not on green wire on the output side, the converter is bad and will need to be replaced. Before replacing the converter, you will want to examine the wiring on the trailer to ensure that nothing has shorted out. Check the connector on both the vehicle and the trailer to make sure they are not damaged or corroded. Trace each circuit back from the trailer connector, looking for pinched or broken wires, or wires with worn or cracked insulation that would allow the copper conductor to short out on the trailer frame or other metal part.
