Troubleshooting Trailer Brake Controller In 2008 Ford F-250 Not Working When Brake Pedal Is Pressed

Updated 09/29/2021 | Published 09/28/2021

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Curt 7-Way to RV Socket LED Circuit Tester - Vehicle End

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Hook Probe Circuit Tester

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Question:

My trailer brakes dont want to work when I apply the pedal but will work with the manual slide. I have 3 trailers and all are the same.

asked by: James H

Expert Reply:

I am sorry to hear that you are having this issue!

Since the issue is not tied to a specific trailer but instead is happening with every trailer then the issue is going to be either how the controller was installed, or possible a bad stop light switch on your truck. With that said if your trailer brake controller is proportional, then it will not have power via the brake pedal unless your truck is moving.

It looks like you were looking at stuff for a 2008 Ford F-250 and assuming that is the vehicle you have the controller should be installed with a plug in adapter so no splicing is required.

Test the red wire going on the back of the controller with a circuit tester # PTW2993. With the brake pedal pressed you should have power, but no power any other time. If you do not have power to that wire even when pressing the brake pedal then the issue is the stop light switch has gone bad.

If for some odd reason the controller was hardwired to your truck instead of an adapter then go ahead and check the stop light switch for a wire that only has power when the brake pedal is pressed, and make sure that is the wire connected to the red wire on the controller.

I included a link to a helpful article that goes over wiring for you to take a look at.

expert reply by: Samuel C