Troubleshooting And Adjusting Electric Brakes On Trailer

Published 09/18/2015

Question:

I followed a previous answer for testing brake magnets but wondered do I test each individual magnet for the ohm reading of 3.2-3.5, or is this a test of the system as a whole? I got 3.4 ohms individually but combining two brakes one axle i get 1.8-2.1 ohms. I have 10inch brakes, ordered and installed new shoes and still can only get one brake to lock when testing the breakaway and the brake controller needs to be maxed out to stop the tuck and trailer at low speeds.

asked by: Mitch C

Expert Reply:

The testing procedure for brake magnets in the attached help article is for testing the entire system, and also further testing for each individual magnet. The first part of the help article is for testing the system. If you should have a reading that is too high or too low you would then start testing the individual magnets on a bench test.

The first chart in the help article shows that the max amps at 12 to 13 volts for 2 brakes as you said you tested should be between 7.5 and 8.2 volts. If you have a multimeter you should be able to see what the voltage is when testing and use the chart to see if your system has the correct output.

You may need to adjust the brakes on your trailer. Many times that is the problem if the voltage is correct and you are still not getting the proper braking.

I have attached a link to a video that shows how to install electric brakes. At about the 4:20 mark on the video, you can check out how the brakes are adjusted.

expert reply by: Jeffrey L