Troubleshooting P3 Brake Controller that Reads No Connection When Connected to Trailer

Published 09/28/2016

Question:

I installed tekonsha 90195 with kit ETBC7 on a 2001 Sierra Express. Its showing no trailer connectedinch Ive checked the all the wires under the brake controller red, blue and black they all check out. Ive connected the trailer, turn signals and brake lights work, but still showing no trailer connected

asked by: Andrew

Expert Reply:

If your trailer is connected to your tow vehicle but the message on your P3 is telling you that a trailer is not connected the problem is most likely due to corrosion on either the 7-way on your vehicle or trailer. Clean both connectors well with fine grit sandpaper and see if that fixes the problem. Make sure the pin isn't bent also. The pin you are looking for is the 5:00 pin on the vehicle 7-way.

There are some tests you can do to determine if this is the issue. I have included 2 links on testing and troubleshooting brake controllers for you that cover the testing.

The P3 can help diagnose problems, but if the controller says no connection there's really no other diagnosing it can do.

expert reply by: Jameson C