Troubleshooting Brake Controller That Cant Detect Brakes On Trailer New trailer

Updated 03/16/2015 | Published 03/13/2015

Question:

So I just bought a new trailer but when I plug it in I get no brakes to the trailer when I push the brakes but when I set the gain to 10 and slide the brake controller they work. The OEM ebc doesnt light up, and on the dash it say trailer disconnected the dealer checked it over 3 times cant slove the problem. I have another trailer which is 24ft enclosed carry-on trailer that works fine no problems when I plug it up. The new trailer is the only one giving trouble

asked by: Paul C

Expert Reply:

Typically when a brake controller only works with the manual override lever of the controller the problem is the stoplight circuit used to wire up the controller. Since your controller works with a different trailer then the problem appears to be related to the new trailer.

Since the controller is not detecting the trailer that would make me think that the brake assemblies aren't grounding properly so the controller isn't detecting them. First thing I would do is check the grounds of the brake assemblies. You may even try running the ground wire from each assembly back to the main ground of the trailer.

Your controller will put a slight draw on the brake output circuit periodically to see if it can find brake magnets. Since your trailer isn't detecting the magnets I would strongly suspect the grounds of the magnets are to blame.

I attached a help article on troubleshooting brake controllers for you to check out as well.

expert reply by: Jameson C