Troubleshooting Brakes of Brinley G3500 no Working

Updated 08/27/2025 | Published 08/22/2025

Question:

Not sure if you can help me. We have a Brinkley 2024 G3500 8k axles disc brakes tow with GMC fully 2024 our brakes for trailer went out while we were towing. Had them tested by rv tech had the the 7 pin checked on truck 2x no one can find anything wrong and still no brakes

asked by: Margaret L

Expert Reply:

Hey Margaret, does the brake controller in you truck have anything unusual on the display like "trailer disconnected" or anything like that? What brake controller do you have in your truck by the way?

expert reply by: Jameson C

Margaret C.

8/26/2025

It says. “o percent output. Brake controll brand not sure it came with truck. I would have look that up. Also on a FB post on Brinkley page I found this The lithium batteries charge at a higher voltage than the truck batteries. Truck notices this and disconnects the brakes. Disconnected the 12 volt black # 7 power wire in the junction box behind the pin box. No more problems with brakes. But the dc-de charger will not work. Maybe need a adapter to go into the seven pin

Jameson C.

8/26/2025

@MargaretC Did you try disconnecting that charge wire and it allowed the controller to work again or was that just a suggestion you read?

Margaret

8/27/2025

It’s what I read

Jameson C.

8/27/2025

@Margaret Yeah I read the same thing too on forums. So not all brake controllers are compatible with electric over hydraulic brake actuator so that can very easily be the problem you have. I would need to know what controller you have though. Also some compatible controllers need to have it set into hyraulic mode.