Troubleshooting Tekonsha Primus IQ Brake Controller Error Code PL

Question:

I have a PL fault code with brake lights staying on. Test shows power to red wire without depressing brake pedal. And brake lights stay on after disconnecting controll unit

asked by: Trevor W

Expert Reply:

Your Tekonsha Primus IQ Trailer Brake Controller # TK90160 is showing an error code. The PL fault is a Power interruption while brake pedal is depressed. It sounds because you have tested the red wire without depressing the brake pedal that you have connected that wire to the hot side of the brake switch instead of the cold side. You want to connect that wire to the cold side so that there is only power on the red wire when the brake pedal is pressed. I've attached an article to assist and recommend using a circuit tester like # PTW2993.

The brake lights staying on after disconnecting the controller is odd. It sounds like the switch may be bad and is running constant power or a slightly interrupted power that may throw that code on your controller and keep the brake lights on. I recommend testing either side of that switch to make sure it is functional.

expert reply by: Jason S