Troubleshooting Overheating and Melted Brake Wire on a Trailer

Updated 02/28/2014 | Published 02/26/2014

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Hook Probe Circuit Tester

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10 Gauge Wire - Blue Primary - Per Foot

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$1.89

Question:

I HAVE A STOCK TRAILER HOOKED UP TO A FORD TRUCK EVERY THING WORKS ON TRUCK. HOOKED UP TRAILER AND APPLIED BRAKES WIRES GOING TO LEFT SIDE MAGNETS STARTED SMOKEING AND MELTED.

asked by: RON K

Expert Reply:

It sounds like there was either a short on the electric brake power wire or the wire gauge running to the brakes was not big enough. Since the wires are already damaged, I recommend running 10 gauge wire, like part # 10-1-1, from the trailer connector to the brake magnets. Smaller wire, such as the wires running to the lights, cannot handle the amperage draw of the brake magnets and will melt.

Replacing that entire wire should also fix any potential short problems as well. Just to be safe, I recommend replacing the wire running to the right side brake magnets as well. I would also inspect the brake magnets inside the hub. If the brake magnet looks worn or if you can see the copper windings on the face of the magnet, I would replace the magnet too.

We experienced a similar issue in our shop recently of the brake wire overheating. We found that the electric brake power wire was pinched at one of the brake assemblies causing a short. This was overheating the wire and once we fixed the short, the problem went away.

expert reply by: John H