Troubleshooting Prodigy Brake Controller That Does Not Work After Sparking at Harness

Question:

My brake controller was working fine, but then while the moving the connector under the dash it sparked on something. Now when I plug in the controller it does not come on.

asked by: Caleb

Expert Reply:

In certain circumstances a brake controller like the excellent Prodigy P3 # 90195 can be damaged by a short circuit. The harness used to install a P3 in a vehicle that has a quick connect port, such as part # 3015-P which fits a 2007 Silverado Classic, has its contacts well protected inside the plastic connectors, but if your controller was hardwired, there is a chance it was shorted out.

You can test to find out by unplugging the controller from the harness, which you will leave connected to the truck. Ground a circuit tester like # PTW2993 to the contact for the white ground wire (see photo, please) and then test the contacts to see if the correct signals are reaching the controller. If the signals are reaching the controller and it does not function, then it is likely that it was damaged and needs to be replaced.

The contact for the red wire should carry a signal ONLY when you have the brake pedal pressed. This is the input signal to the controller that tells it to send power to the trailer brakes. Next test the contact for the black wire. This wire brings 12V power to the controller to operate it. If you do NOT detect either of these signals you may have a blown fuse in the vehicle. Check the power distribution box for any fuse related to trailer brake controller power.

expert reply by: Adam R