Trailer Brakes Wont Lockup with Brake Controller at Full Power

Updated 06/03/2019 | Published 05/31/2019

Question:

I have a dodge ram 2500 and have the brake controller set to 10 gain. Im pulling a utility trailer with GVW of 4400. The brake controller instructions say to drive 20mph and apply the trailer brakes manually using the slide to see if brakes lock up. Then, adjust gain downwards until they dont. My brakes wont lock up at 20 mph. However, in my driveway, I put the truck in N. I have a slight downwards slope. I put the truck in N and let it start going. Then, I manually applied the trailer brakes only using slide and the brakes engaged and stopped the truck and trailer. Am I OK as is? Or do I have some problem?

asked by: Doug

Expert Reply:

The brakes on your trailer should be locking up if you have the power set to the highest setting. If they do not then you will first want to be sure the brake controller is putting out a full 12 volts. If you sever the blue wire from behind the controller and apply the manual override at the highest power setting you should see 12 volts. If not 12 volts then replace the brake controller. If you do get 12 volts then start checking varying points on the brake output wire until you get to the braking assemblies. The voltage will drop off the further you go back but not by too much. If it does then you will need to look for a short.

If you are getting close to 12 volts at the braking assemblies then first make sure your brakes are adjusted properly but otherwise you would need to test the brake magnets (see article). If you like, you can try some boost settings (if applicable) to see if that will lock up the brakes while at speed.

expert reply by: Conner L