Troubleshooting Curt Wiring Harness with Running Lights Not Functioning on 2013 Ford Fusion

Question:

I installed a Curt trailer wiring kit on a 2014 Fusion a few years ago. Everything worked. There is no wire from the car to the controller for the running lights, but somehow the controller could sense when the running lights worked. Now I have moved the controller to a 2013 Fusion and the turn signals work but the running lights do not. There is no voltage at the plug on the on the back of the car. How does the running light system work without a sense wire? Thanks

asked by: Daniel R

Expert Reply:

The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # C56351 is the correct fit for both 2013 and 2014 Ford Fusion models. The harness does not "sense" power using sensors but rather is a direct plug into that wiring circuit. Since you are getting no running lights, I recommend disconnecting the left and right side to check for bent pins and then make sure the ground is connected bare metal to bare metal.

Using a little dielectric grease # 11755 may also help with the connections to keep moisture out for correct function.

Finally, if the issue hasn't been resolved, you can use a circuit tester like # PTW2993 to test the functions going into the black box and coming out of the black box to see if the module is bad.

expert reply by: Jason S