What Could Cause Brake Controller On 2018 Ford F-150 To Only Work With Manual Override Lever?

Updated 06/19/2023 | Published 06/16/2023

Question:

Why Would Trailer Brakes Only Work With Manual Override Lever and Not Brake Pedal I have a 2018 Ford F150 Lariat Supercrew FX4 4x4. Ive installed an aftermarket trailer brake controller and enabled it via forscan. Ive had issues with the battery draining and Im required to pull the trailer brake controller fuse to keep this from happening when not towing. However, when towing, the trailer brakes only work with the manual override lever and not the brake pedal. Whats going on? The part I ordered from Amazon Hope you can help Paul

asked by: Paul M

Helpful Expert Reply:

I do not know which controller you used, but if the manual override on your controller is working but not with the brake pedal the red wire of the controller is hooked up incorrectly.

If you're using a custom install harness like the # 22292 you will need to test the pin that feeds the red wire of the controller with a circuit tester # PTW2993. It should have power only when you apply the brake pedal.

If it does not you'll need to check that your stoplight switch on your truck is working, which the easiest way is having a friend stand behind your truck and make sure your brake lights come on when you press the brake pedal.

If you can tell me what exact controller and harness you used to install the controller I can try to be a little more specific.

expert reply by: Samuel C