Troubleshooting Weak Trailer Brakes and Brake Controller that Randomly Activates Brake Lights

Published 12/03/2014

Products Featured in This Question

Wiring Kit for 2, 4, 6, and 8 Brake Electric Trailer Brake Controllers

(164)

$56.76

Tekonsha Plug-In Wiring Adapter for Electric Brake Controllers - Ford, Lincoln, Mercury

(1798)

$19.06

Question:

I have a 2006 Ford F150 Lariat Pick up truck with a Husky Journey HD electric brake controller. I have a tandem axle flatbed 20 ft utility trailer which I pull with it. Both axles are equipped with electric brakes. Each axle is rated at 6,000 lb. The braking force is greatly reduced from what it has been. I have the brake controller set at 55. At one time it was sufficient to be effective for stopping a load of 6,000 lb. Recently it has stopped working correctly. I adjusted the brake shoes on all four hubs but did not help. Upon applying the brake in the truck I could still turn one of the jacked up wheels on one side of the trailer with my hands. All four axle hub brake assemblies are receiving a signal from the controller as I can hear them activate when the pick up brake is applied. On another note over the years I have witnessed my pickup brake lights coming on when no one is around it and not hooked to a trailer. Upon inspection of the pickup I noticed that the brake controller is activated. This is very strange. Do you think I have a problem with my controller? If so is a replacement available to match my wiring pigtail to avoid rewiring?

asked by: Robert B

Helpful Expert Reply:

It sounds like you have a problem with the brake controller. Especially because of the issue you have where it sounds like the brake controller is either being activated by the brake lights or is backfeeding voltage on to the brake light circuit.

Here is how to test the brake controller to determine if it is the problem.

Sever the blue brake output wire near the brake controller leaving enough room to reconnect it and then apply the manual slide. Using a circuit tester like the Quickee Tester, part # 3808, you should get output to the controller side of the wire you severed. If the manual slide activates the trailer brake output wire properly, try the brake pedal. If the brake pedal activates the brake output properly also then the problem is farther back either in the vehicle wiring or on the trailer.

If either the brake pedal or the manual slide are not functioning properly you will need to test the wires going into the brake controller. Make sure you have power entering the brake controller on the black wire. On the red wire you will only want power when the brake pedal is pressed.

If there is power on the red wire before the brake pedal is pressed you have connected the red wire from the brake controller to the wrong circuit. You would then need to find the brake switch wire that has power ONLY when the brake pedal is activated.

If these connections check out and the brake controller is properly grounded then there is possibly a problem inside the brake controller.

I am including a link to a video that will show you how to test the wiring on a brake controller.

For a replacement brake controller I would recommend the P2 part # 90885. This is our best selling controller because of how well it works and how easy it is to install. You will need to hardwire the four wires of controller to your harness or use the # 3035-P to install the controller.