Blank Display and PL Error Code on a Tekonsha Trailer Brake Controller, 1996 Chevy 3500 Diesel

Question:

I have had this brake controller installed in my 1996 Chevy 3500 diesel since July and never had a problem with it. The other day when I plugged my gooseneck into the bed plug it acted as if it was not getting any power blank display and does not react to any buttons or the manual slide. Today when I plugged my bumper pull into the under bed plug I have the same problem. Randomly it will display the P.L. error, but not regularly or very often. I have checked where I have the box wired into the truck and replaced/redone them all. I have also cleaned the ground under the hood of the truck and retightened it and still am not getting power to the brake box. Any suggestions?

asked by: Elise

Expert Reply:

The PL error code on your brake controller indicates that power to the unit has been interrupted. I would check several things to determine what the problem is. Some of this may seem redundant since you have done a lot of troubleshooting already. Since you first encountered the problem when you connected the gooseneck to the in-bed connector, I would check the grounds for both the truck side and trailer side to make sure there is no corrosion and that they are attached properly. You can also check for corrosion on the pins of the connectors as that could lead to a short.

Next, I would check the wiring for the brake controller. Since you are not getting power to the unit, check the black wire using a circuit tester like # PTW2993 to see if it is receiving power. If it is not, then there is a break in the wiring or the circuit breaker between the battery and brake controller is bad. If it is getting powe7r then something is wrong with the internal components, and it will need to be replaced.

You can also check the red wire. Using a circuit tester, probe the red wire on the back of the brake controller while you step on the brake. If you are not getting a consistent reading then the connection to the brake switch is causing the problem. You will want to connect the red wire to the wire on the brake switch that carries a signal only when the brake pedal is pressed.

If the red wire is producing the correct signal, you can move on to testing the blue wire. Probe the blue wire while stepping on the brake and then again when using the manual override to check for a signal being sent back along the blue wire. If there is a signal, have someone test the pins at the connectors to see if the signal is getting through. If it is not, then you know there is a break in the wiring somewhere.

If there is no signal coming out of the brake controller along the blue wire, then something is wrong with the internal circuitry of the brake controller, and it will need to be replaced.

expert reply by: Michael H