Trailer Brakes Apply Only Weakly When Brake Controller is Set to Maximum

Updated 05/06/2015 | Published 05/05/2015

Question:

I have a new ram 3500 equipped with trailer brakes. I can turn the box up to 10 which is all the way up and the brakes hardly grab on the trailer ,thats manually.

asked by: Jamie

Expert Reply:

The best way to troubleshoot your weak trailer braking is to disconnect the trailer and apply 12V power direct to the trailer's brake circuit. This will tell you if the issue is in the trailer or the truck's brake controller or wiring.

When you apply 12V power to the trailer connector the brakes should engage fully if they are adjusted properly. If your brakes do not lock up they may need adjustment (if they are the manual- adjust type) or you could have a ground issue on the trailer. Make sure the main trailer connector's ground wire is tightly attached to a clean bare metal surface on the trailer frame and that the ground for each brake assembly is also secured to a clean bare metal surface.

If the brakes lock up when you apply 12V power directly then you know the issue is in your brake controller, the vehicle's trailer wiring (again a bad ground could be the problem) or on the vehicle connector. Inspect and clean all connectors as necessary.

Please feel free to let me know the brand and model of your brake controller and the model year of your truck.

It is common for people using factory brake controllers to end up replacing them with a superior aftermarket unit like a Prodigy P3 # 90195. If you have a 2014 Ram 3500 you could install this controller using a quick-connect adapter # 3023-P which plugs in to the under-dash port, as shown in the linked video.

expert reply by: Adam R