SH Error on P2 Brake Controller with Any Trailer Plugged In

Question:

Hi, I have a Prodigy P2 which shows the normal . . when no trailer is connected. As soon as I plug in a trailer with brakes using a 7 pin it shows the S.H. error. I tried many trailers while diagnosing and all trailers, all makes, all gave the S.H. when hooked up. I read that constant S.H. likely points to brake controller, S.H. only when trailer is connected likely points to the trailer as fault, but at some point when it does it on all trailers there must be a different problem ? Any thoughts ?

asked by: Wayne

Expert Reply:

The SH error on the P2 brake controller # 90885 indicates a short circuit. The most likely culprit is a dirty or corroded vehicle side trailer connector. Check the connector on the truck and make sure it is clean inside, where the wires attach, and outside on the pins. You can also inspect the wiring from the connector that goes to the front of the truck and fix any exposed wires.

If this does not fix the problem, there are other tests you can perform. In the truck cab you will need to sever the blue wire several inches from the back of the controller. Then use a circuit tester such as # PTW2993 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override. If it shows power at idle, then there is something wrong with the controller and it will need to be replaced.

If it tests fine then reconnect the blue wire. Then move on to the truck side trailer connector. You can test the brake output pin and it should only show power with the manual override. If it shows power any other time then there is a short somewhere between the connector and the brake controller you will need to track down.

I have also included some help articles on testing and troubleshooting brake controllers for you.

expert reply by: Michael H