Trailer and Vehicle Brake Lights Do Not Come On When Headlights Are On with 1999 Plymouth Voyager

Question:

Everything works well on the 1999 plymouth voyager and the trailer 4 pin with headlights off. With headlights on, all is correct except the brake lights do not work on the van by itself nor do the trailer brake lights when connected. Help ! thanks!

asked by: Tom G

Expert Reply:

The problems you are describing are typically associated with a poor ground connection, but it could also be the result of a faulty converter box if you are using a plug-in style wiring harness like the Curt T-Connector Wiring Harness, # C55334, that you referenced.

If the wiring harness was working in the past and the problem just started, then the converter box could have shorted out, which would cause a variety of different issues. If this is the case, then I recommend replacing the wiring harness with a new harness. The Curt T-Connector harness that you referenced is compatible with your 1999 Plymouth Voyager.

If you recently installed the harness, then it may be possible that a wire was pinched or frayed. I recommend inspecting all of the wiring looking for any sections that were damaged and repair or replace as needed.

If you did not use a plug-in style wiring harness or if your wiring harness had a separate ground wire, make sure it is attached to a clean and bare metal surface. You could even use an extra length of wire to run it to the negative post of the vehicle battery.

If you cannot find the problem or come up with a solution after following these steps, let me know what you come up with and we can do further troubleshooting.

expert reply by: John H