Troubleshooting Smoking Brake Controller and Melting Wires

Updated 09/21/2018 | Published 09/20/2018

Products Featured in This Question

Hopkins Replacement Break-Away Switch, 7" Lead Wires

(149)

$12.55

Hook Probe Circuit Tester

(60)

$13.03

Question:

My brake controller in my car smoked up with wire and plastic melting. Would this damage any other cable/wire in the car. How do i find out. Is the brake controller usable if it is still displaying nos. I am told the electric breakaway cable pin needs to be permanently attached to the breakway box even when the trailer is in storage. I normally remove the battery and cable when not in use. How do i confirm if the mechnisms are working properly and the trailer magnets and brakes are not impacted. What wires in the car are normally needed to be checked. Will their be any melting of wires in the car even after the brake controller and trailer was immediately disconnected. Where to locate fuse for brake controller in car. Can someone help to understand how this brake controller functions, precautions and safety. Will i be able to tow my trailer back on road.

asked by: Vai

Expert Reply:

A trailer brake controller should never smoke up like how you described. The first thing you will want to do is determine what caused this, so it doesn't happen again when towing a trailer. The most likely culprit is an internal short on the brake controller itself, which would just require a full replacement. You will also want to make sure that the wiring connections are all correct. The red wire from a brake controller should go to the cold side of the brake light switch in the vehicle. This is the wire above the brake pedal that ONLY gets power when the brake pedal is depressed and no power with any other function. Using a circuit tester like # PTW2993 to test the vehicle wires is the best and safest method for verifying the correct one.

You can also inspect the blue wire coming out from the back of the controller as it goes back toward the 7-Way for any damaged or exposed sections. I do not recommend using your existing brake controller again, regardless of where you determine the issue came from as it was likely still damaged during the incident if it wasn't before.

I really can't be sure if the issue you experienced affected any other wires or components on the car. Your best bet is to simply inspect all of them.

The breakaway switch on the trailer is powered by the trailer battery. Removing the battery and cable from the trailer while it's in storage is a good idea to prevent the battery from losing its charge especially if you live in a colder area.

For any fuse locations on your vehicle you will need to check your copy of the owner's manual. All of their locations and functions will be listed under the section "Fuses and Relays".

If you can tell me what brake controller you were using and what vehicle you have I will be happy to provide some more specifics on its operation and how it should wire up to the vehicle. I have also attached a couple articles that you might find helpful.

expert reply by: Chris R