Troubleshooting Brakes Not Working on One Side in Mountains

Updated 04/24/2025 | Published 04/12/2025

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Question:

I’ve had my dual axle trailer brakes checked and double checked and am assured that they are functioning properly in a shop environment. However, during prolonged mountain terrain braking I am only getting effective braking on one side as indicated by a 307 degree drum temp on one side vs 110 on the other. While sitting still and applying the brakes theirs is a noticeable hum from each of the four brake drums. Under no-braking Highway driving there is virtually no temp difference in the drums. The only other possibility that I can think of is the DrawTite controller has become faulty after 9 years. I’m unable to determine which model it is but it’s a plug-and-play model for a 2015 Ram. Thanks in advance for your help.

asked by: Vincent Z

Draw-Tite Activator
(click to enlarge)

Expert Reply:

Hi Vincent; have you tried checking the voltage at the brakes with a circuit tester # PTW2993? Perhaps one side has a weak ground compared to the other or for whatever other reason isn't getting the same amount of power.

Since the brake controller sends power down a single brake output line and the brakes function I don't think the brake controller is your issue. However, it wouldn't hurt to check the brake output line just to be sure. It sounds like you're getting more braking force on one side vs the other which normally wouldn't be so obvious but with the conditions in the mountains it is very noticeable.

Are these self-adjusting brakes or do you manually adjust them? One side could be overadjusted which would cause the same issue.

expert reply by: Robin H

Vincent Z.

4/23/2025

Hello Robbin, I had my RV tech double check all accessible brake related wiring and connections and to verify that when he had the drums off and then reinstalled that all was in proper order. The brakes on the Dexter never adjust brakes were adjusted at this time also. Thanks VincentZ

Robin H.

4/24/2025

@VincentZ and you had this problem before and after they looked at it? What do you mean the never adjust brakes were adjusted? The idea behind them is not to manually adjust them. It can be done but if it is overdone it is incredibly difficult to back off. So is it a single drum that is heating up? Did they check for a bent spindle? If everything checks out it sounds like the problem is potentially something like that and not so much the brakes.