If you Put 12 Volts on Brake Output Circuit Should Trailer Brake Assemblies Make Noise

Published 07/17/2023

Question:

I am trying to troubleshoot my brakes on my car trailer . It has 3 7000 lb axles with brakes on all 3 axles. If i connect a 12v battery to the blue and white wire of my 7 way plug should i hear the magnets engage on the drums ?

asked by: George D

Expert Reply:

If you connect 12 volts to the blue wire of your trailer wiring you should hear the brake magnets click and then hum. If you aren't hearing that you have a wiring problem which is most likely a bad ground or a short on the blue wire. If you also add the white wire as a ground that would also troubleshoot that.

You'd want to go over the wiring to see if you can find anything that's an obvious problem and fix as needed.

expert reply by: Jameson C