Trailer Brakes Humming When Connected to Tow Vehicle

Question:

I have a buzzing on my trailer brakes as soon as I connect to the truck outlet plug,testing with a incandescent tester the light barley comes on when testing the brake pin on the connector but if the brakes are applied then it goes to full brightness,the brakes do work theres just a very noticeable buzzing when the brakes ore not being applied.

asked by: Dave

Expert Reply:

The trailer brake controller on your tow vehicle will send a small pulse charge to sense if a trailer is connected, so the small amount of power you are testing at the brake output pin on the 7-Way without the brakes engaged is normal.

If you are hearing a buzzing or humming sound coming from the brake assemblies though as soon as you connect the trailer (without engaging the brakes) then I do recommend inspecting the wiring around brakes to make sure there aren't any exposed or pinched areas that need to be addressed. Make sure the ground wires are also securely connected to clean, bare metal surface on the trailer frame.

If all the wiring looks good I recommend simply verifying that when this buzzing is occurring the brakes aren't actually grabbing. If they aren't grabbing and everything is working as it should then the buzzing shouldn't be a concern.

expert reply by: Chris R