Tekonsha Primus IQ Trailer Brake Controller Shows PL Error Code on 2011 Cadillac Escalade

Question:

I installed this in my 2011 escalade and I get a P.L. in the display every time I depress the brake. Its a power interruption according to the troubleshooting chart. I connected a trailer to it and no change in the display. The brakes on the trailer do work but adjustment cant be read on the screen but I can effect it with the adjustment wheel. All connections are correct and the truck was prewired. What typically would cause that, could I have a defective unit?

asked by: John M

Expert Reply:

On the GM tow package wiring under the dash of vehicles like your 2011 Cadillac Escalade, there are typically 5 wires: ground, 12 volt power, output to trailer brakes, input from stop light switch, and illumination. If you have the brake controller red wire connected to the illumination wire this may be causing the problem.

It is also possible that there is a bad ground connection. You can test this by attaching the white brake controller wire to the negative battery terminal of a separate battery. It the error code goes away then you know there is a bad ground and you will need to attach the white wire directly to the negative battery terminal on the vehicle.

To determine if the brake controller is bad, sever the blue wire several inches from the back of the controller. Then use a circuit tester like # PTW2979 if needed to test the end coming out of the brake controller. It should only show power when you apply the manual override. If it shows power at any other time then the controller is bad and will need to be replaced.

You can also make sure that the vehicle side connector at the back is clean and corrosion free. Check the pins and the back where the wires attach for corrosion.

I have included a link to an FAQ article on troubleshooting brake controllers for you.

expert reply by: Michael H