Trailer Brake Controller Displays Random Numbers when Moving or Stopped and Brakes are Hot

Question:

The numbers on the readout are random, rapidly scrambled. This can be when I am moving or stopped. When I get out of the truck I can hear a slight clicking at each hub. The vehicle is a Ford Expedition 2004. The hubs also seemed very hot. What is happening?

asked by: Jerry

Expert Reply:

It sounds like you need to inspect the brake magnets and the wiring to the brakes, trailer connectors, and the brake controller connections. The brakes being hot makes me think that the magnets could be going or that they need to be adjusted or the pads replaced.

To test the magnets, you can start with a visual inspection. If you can see the windings coming through they will need to be replaced. Also check the ground and power wires to make sure they are intact with no nicks touching metal surfaces and causing a short. Grounds should be short and attached to a clean bare metal surface.

To further test the magnets, you can use the FAQ article I have linked for you. You may need a multimeter, # PT89ZR, to perform the tests.

Also check the trailer side and vehicle side connectors for dirt and corrosion and clean them out. Corrosion can also build up behind the connectors where you cannot see it. Dirt/corrosion can cause a short circuit situation and malfunctions.

Make sure that all of the connections for the brake controller are correct. You should be using harness # 3035-P. I have linked instructions for you. make sure your harness is pinned out like the diagram. You can also use the multimeter to check the connection point on the truck to make sure all the wires in the harness are in the right place.

If everything is wired as it should be, the magnets are all checking out alright, and the connectors are clean then the problem is most likely in the brake controller and it will need to be replaced. Brake controllers do not have internal user serviceable parts.