Trailers Electric Brakes Not Functioning, But Show 12V at Brake Signal Wire on Brake Assembly

Updated 05/31/2016 | Published 05/27/2016

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Digital Multimeter with 42" Long Test Leads - XL LCD Display

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Question:

Trailer brakes not working, I have 12 volts to the wiring coming out of the new brake plate but no brakes

asked by: Paul

Expert Reply:

Since full power is reaching your trailer's brakes, but they are not working properly, I recommend checking the ground for each brake assembly. It is important that the brakes are grounded to a clean, bare metal surface of the trailer. Dirt, corrosion, and rust can all interfere with a ground.

If they are not already, I recommend grounding all of the brake assemblies to the trailer's main ground. You can use 10-gauge wire # 10-1-1, to route all of the brake assemblies' grounds to the main ground. This will help provide a more suitable ground for your brakes.

In addition to the ground for the brake assembly, another component to check is the brake magnet. Since 12V are reaching the assembly, the problem could be that the magnets are not working to activate the brake. You can use a multimeter, like # PT29ZR or the one used to test the volts on the brake signal wire, to test the magnets for proper function. I have attached a help article on testing brake magnets for you.

expert reply by: Victoria B