Troubleshooting Brakes Locking Up on 2019 BigTex Car Hauler

Updated 05/28/2025 | Published 05/17/2025

Question:

2019 Bigtex 70Dm car hauler. 2019 Ram with built in, factory brake controller. I have constant 12v coming out of the plug on the truck and its locking my brakes up, even with the controller turned down all the way. I actually took the trailer plug apart, unscrewed the corresponding wire, and tucked it back. That way I can use the plug for lights but just dont have brakes. Im getting ready to sell the trailer and the brakes need to be working. I tried to explain the issue to my local Dodge dealer and they were clueless. Like talking to a brick wall.

asked by: Jay H

Expert Reply:

Hey Jay, thanks for reaching out!

The only way your trailer brake controller pin will have constant 12V power is if the brake controller on your Dodge is broken, or if the wiring is damaged and the 12V power pin is bleeding over to the brake controller pin.

Since it sounds like the issue is on your truck side of things, you should be able to just put that wire back in place on your trailer and be good to go. You can verify this works by hooking the trailer up to a different truck to see if everything operates like it should.

Am I understanding your situation correctly, and does this help you out some?

expert reply by: Jon G

Jay

5/28/2025

Hey Jon, thanks for the response! It was the truck. I replaced the break away switch and the battery and nothing changed. I had a guy coming to get it, we hooked it up to his truck and no problems.