Troubleshooting No Trailer Connection Message on Tekonsha P3

Updated 09/09/2021 | Published 09/07/2021

Question:

I have everything hooked up and my trailer plugged in but it say on my screen that no trailer is connected. My tester is showing a dim light from the blue wire. Any suggestions? Could this be a grounding issue?

asked by: Tyler B

Expert Reply:

I would start by inspecting the connection on both your vehicle and trailer. This issue is often caused by corrosion on the 7-way connections. It probably wouldn't hurt to clean the connections one way or another.

If this does not solve the problem then we will move on to wiring. I would check all of the brake controller connections and make sure they are good. If you had a plug-in connection try unplugging it and plugging it back in to make sure it is seated firmly. This would also be the time to check the ground connection. If you aren't sure about it, you may want to try moving it to see if it solves the problem.

Once this is done I would move on to testing the wires. Since I don't know where you checked the wire at, start by testing the blue wire behind the brake controller. If no power is present it may be that the controller is malfunctioning. If there are no issues move back to the 7-way connection on the vehicle. If this is where you tested originally and found low or no power, you will need to inspect the wire for a short. If there is no issue at the vehicle 7-way you want to continue to test, working your way back toward the magnets.

I have attached some helpful articles that go over troubleshooting brake controllers in greater detail for your reference. If you are unable to locate the problem please reach out and I will help you troubleshoot further.

expert reply by: Robin H