Troubleshooting Trailer Brakes Locking Up w/a Factory Brake Controller on a Ram Truck

Updated 12/01/2025 | Published 11/11/2025

Question:

My horse trailer brakes lock up if the brake pedal is pushed, no matter the gain, but work perfectly if the squeeze modulator on the dash is used. This is a factory installed brake controller on a Ram 1500. Just not sure where to start.

asked by: Chris

Expert Reply:

Hey Chris, welcome back. It's either a faulty factory brake controller or an issue with your trailer's brakes. Seeing as how they are responding normally with the manual override pressed I would lean towards it being the factory controller. I don't have anyway to test it or troubleshoot it but a quick way to figure out if it's the problem is to hook your horse trailer up to another vehicle and see if the brakes work like they're supposed to.

If it's the trailer, then I would start by testing the wiring for any faults. Possibly even a bad ground. If this just started I can't see it being the brakes over-adjusted but you can check that too.

What year is your truck and is it a Classic? If it's a 2015 - 2027 Ram 1500 you can replace your factory controller with the Redarc Tow-Pro Liberty Brake Controller w/ Custom Harness item # RED87CR. The included harness will plug directly into where your factory setup is now. The only part of it you will see is the control knob.

You can add this information and any other questions you have where it says Reply to Jerred H and I'll be happy to answer them.

expert reply by: Jerred H

Ram Factory Brake Controller
(click to enlarge)

Jerred H.

12/1/2025

Hey Chris, did you get a chance to test your horse trailer with another vehicle to see if the brakes still locked up? Knowing how that went could help confirm whether the factory controller was the issue. Your update could make it easier for others with the same Ram setup.

Chris

12/1/2025

@JerredH she ended up trading the truck in, so she has yet to hook it up to the new truck but we will k ow soon if it was old truck or trailer. Thanks for checking in again.