Trailer Brakes

Gdetrailer wrote:

jkwilson wrote:
How do you know the controller isn’t activating the brakes? Did you use a compass or listen for the hum at the wheels?

DC does not "hum", "buzz", "sing" or play any tune, you will not hear a thing.

Newer brake controllers while they do employ PWM to control the braking output operates at a very reduced output when you are sitting still. Even the manual lever output is reduced and does not apply full braking voltage when sitting still.

Even on older brake controllers, I never had any luck getting a compass to give a decent repeatable indication. There is a huge chunk of iron (drum) between the magnet and your compass. That drum absorbs and redirects a lot of the magnetic fields generated by the electro magnet and by the time it gets to your compass is very, very weak.

What I have found as 100% reliable way to trouble shoot is to jack up one side at a time and roll the wheels by hand and pull the break away pin. Wheels must stop as soon as the pin is pulled.

The breakaway system is supposed to apply full battery voltage from the trailer battery to the trailer brake magnets, if the breakaway system isn't working, then very good chance your truck system isn't going to make the brakes work either (IE trailer wiring problem)..

Put pin back in and you should now be able to roll the wheels by hand again. If they don't stop, then you need to access the wires behind each backing plate and verify that you have or don't have voltage with the breakaway pin pulled (note, the magnets are not going to melt either as per another Internet myth).

No voltage at backing plate then you have a break before the axles.

Voltage at the backing plate then you need to check the mechanicals behind the drum.

If you lift in the correct place, you can lift both wheels on the same side at a time.