Troubleshooting Brake Light and Turn Signal Not Working on Trailer with 2015 Ford F-150  

Question:

Expert Reply:

In order to troubleshoot your brake light and turn signal not working I would start by checking the 7-way connection between your 2015 Ford F-150 and trailer. You want to check for any damage or corrosion which may be what is causing the lights to not work. Whether corrosion is present or not, it wouldn't hurt to clean the connections just to be sure.

If you still have an issue the next thing to check is all of the ground connections. You want to make sure that they are secure and on a clean, bare-metal surface. If that does not solve the problem, I would double check the wire connections at the back of your 7-way. If you have factory wiring, make sure all of the connections are seated properly. If you have a 4-way plugged into a 7-way adapter, make sure that connection is seated properly.

If that still does not solve the problem it is time to test the functions. Using a circuit tester, like the # PTW2993, check the functions on your 7-way connection on your vehicle. If everything checks out here then you know it is your trailer that is the issue. If that is the case, you probably need to check the wiring on your trailer for a short.

If there is a problem at the 7-way on your vehicle, it is probably safe to rule out the trailer as the issue. The idea is to work your way back until you find where the problem is coming from. I don't know your specific setup for wiring here, or whether it is just one turn/stop or both, but you will want to trace back and continue to test until you are able to find the problem. It is possible there is a loose wire on a connector or a short somewhere.

I have attached a helpful article on troubleshooting 4-way connections for your reference. This goes over some of these steps in detail and applies to your situation since the lights that aren't working are part of the 4-way functionality.

expert reply by: Robin H

0