Troubleshooting Manual Override that Won't Work to Lock Up Trailer Brakes

Updated 09/12/2019 | Published 09/11/2019

Products Featured in This Question

LCD Digital Circuit Tester

(28)

$28.06

Brake Adjustment Spoon for Drum Brakes

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$8.08

Question:

I replaced my old controller with the Tekonsha p 3 controller and I have a 2001 GMC Sierra 2500 hd. I have only tried it on my empty 18 foot car hauler but no matter what adjustments I make I cannot get the brakes to lock up to adjust them! And they won’t hold with the manual override! I’m wondering if this is normal for a single axel trailer?? Thanks for your help

asked by: Doug

Helpful Expert Reply:

The signals to send power to your brakes through your brake pedal and through the manual override on your Tekonsha P3 # 90195 are completely separate so it sounds like there is an issue stemming from either the trailer wiring or brake assemblies.

Start by making sure your brake assemblies are properly adjusted. Use a tool like # W80630 (as shown in the "Trailer Brakes and Wiring Installation" video below) to turn the star wheel until the drum tight enough that it is barely able to be turned by hand. Then, go back about 10 clicks - your brakes should drag slightly.

Another thing is to perform a visual inspection of the brake magnets and wires. If you find any exposed copper windings on the face of the magnet that is a sure sign they need to be replaced. Also check for pinched or frayed wires and repair if necessary. Make sure your ground is securely connected to a clean metal surface.

To ensure you are getting proper power to your brake assemblies you can use a tester like # PTW2992 to check the voltage. Both wires (power and ground) on the magnet should put out around 12-13 volts when testing at the highest setting on the brake controller. I have also attached a video for you to reference.

If after going through the above steps you are still not able to find the problem, just let me know and we can troubleshoot further.