Trailer Brakes Hum But Do Not Work on 5th Wheel Trailer

Question:

I just purchased a 1992 Kit Companion fifth wheel. When towing it home we noticed the brakes did not feel like they were working. I jacked up the trailer, applied the truck brakes, the controller is light up as well. I went to the axle and the magnet is humming, but no brakes. I unplugged the trailer connector and adjusted the brake shoes and retested. Still not brakes. I am not sure if the magnets are bad, or if the brake hubs need to be replaced. There was a large amount of spider webs in there I cleaned out, and made sure the shoes do move. I do not want to just start replacing things that do not need to be replaced. Any advise would be great.

asked by: Allen

Helpful Expert Reply:

If the brake controller you are using is a proportional controller then it will not necessarily engage the trailer brakes unless it sense movement. Instead of testing it with the brake pedal, do the test with the manual override lever. Make sure the power output is set high enough as well. A brake controller needs to be adjusted every time you tow a different trailer or the weight on the trailer changes.

If it is still not working then it could be a wiring or magnet issue on the trailer. Since you have already adjusted the brakes and made sure they move freely we can skip that part and go on to the wiring. Make sure that the vehicle and trailer side trailer connectors are clean and free of corrosion. Also check the backs of the connectors where the wires attach.

Then inspect the wiring leading to the brake magnets. Fix any breaks or loose connections. Make sure the ground wires for the magnets are attached to clean and corrosion free bare metal surfaces.

Next you can visually inspect the brake magnets. If you can see the windings coming through then the magnets will need to be replaced. To further test the magnets you can follow the FAQ article I have linked for you. You will need a multimeter, # PT89ZR, if you do not already have one. I have linked the brake magnets that we currently offer if you determine the magnets need to be replaced.

If the trailer checks out fine then there must be some issue with the brake controller. I have included a link to troubleshooting brake controllers for you as well.

expert reply by: Michael H