Pulsing Click from P2 Brake Controller on a 2003 Chevy Avalanche

Question:

Was towing our camper yesterday and noticed a sound coming from what appeared to be the brake controller. it was a steady pulse. No code, brake controller worked fine. This is on a 2003 Avalanche and was installed with etrailer harness. Dropped off the camper, drove home no noise. Tekonsha Prodigy P2

asked by: Mason M

Expert Reply:

This is the first time I have heard of this issue on the P2, # 90885. Usually when a brake controller is making a pulsing click of some sort it indicates a possible short or even feedback from the trailer.

To see if it was the trailer or the brake controller you would have to simulate a load on the brake output circuit on the trailer connector and then drive around and see if it happens again. If it does then it is likely the brake controller. If it doesn't then trying with another trailer with electric brakes should show that it works just fine.

There are some ways you can test the controller. In the truck cab you will need to sever the blue wire several inches from the back of the controller. Then use a circuit tester such as # PTW2992 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override. If it shows power at idle then there is something wrong with the controller and it will need to be replaced.

If it tests fine then reconnect the blue wire. Then move on to the truck side trailer connector. Many times, dirt or corrosion can cause a short in a trailer connector. Make sure the truck and the trailer side connectors are clean and free of corrosion inside and out.

You can test the brake output pin and it should only show power with the manual override. If it shows power any other time then there is a short somewhere between the connector and the brake controller you will need to track down.

If the truck side checks out fine then it could be the wiring to the brake magnets or the magnets themselves. Inspect the power wires to the magnets and look for pinched, frayed, or damaged wires and fix as needed. Make sure the ground wires are attached to clean and corrosion free bare metal surfaces.

You can visually inspect the magnets and if you can see the copper windings coming through the magnets will need to be replaced. To further test the magnets you can follow the help article I have linked. I have also included some help articles on testing and troubleshooting brake controllers for you.

To make sure, you should be using harness # 3015-P on your 2003 Chevy Avalanche. I have included a picture showing how the wires should be arranged on the end that plugs into the truck. Make sure yours matches.