How to Test the Brake Controller on a Trailer

Towing a trailer with your vehicle can present quite a challenge without the proper setup. A loaded trailer can weigh several thousand pounds, which may cause all of your tow vehicle's systems, such as engine, transmission and brakes to work harder. Trailer brakes work on electrical current from the tow vehicle. The brake controller senses when the tow vehicle is slowing down or stopping and sends current to the trailer brakes when needed. This function can prove a lifesaver if you have the brake controller adjusted properly. Learn how to test the brake controller to see whether your trailer brakes are doing their part.

• 1

  Hitch the trailer to your tow vehicle. Connect the safety chains and wiring connector to your tow vehicle as if you were leaving for a trip. Warm up the trailer brakes by applying slight pressure to the manual brake lever on the brake controller while driving at approximately 45 miles per hour for 1/4 mile.

• 2

  Drive at 25 miles per hour (mph) on a level, dry road, and move the manual brake lever on the brake controller all the way to the side. Make a note of the trailer braking action.

• 3

  Increase braking power by turning the power knob on the brake controller to a higher setting if you felt very little braking action. Decrease braking action by turning the power to a lower setting if the trailer brakes grabbed or skidded.

• 4

  Test the trailer braking action again by driving at 25 mph and sliding the manual brake lever over. Repeat the procedure until you feel a moderate amount of braking from the trailer, without any grabbing or skidding.

• 5

  Drive at 25 mph and apply your tow vehicle's brakes, which should also apply the trailer brakes at the previously adjusted braking pressure. Make final adjustments to the power control on the brake controller until you feel a unified braking feel between the tow vehicle and the trailer.