Troubleshooting Weak Braking Signal on Prodigy P2 Brake Controller 90885 in 1997 Chevrolet K2500

Question:

Hello , I have a 97 Chevrolet K2500 , I have bought a Prodigy p2 controller , 7 way Hopkins plug , and a direct fit T connector from Hopkins for lights . I connected and used 2 of my trailers tonight noticed the brakes to do not appear very strong , even on boost 3 with setting adjusted to 13 the wheels never lock up or even close trailers both empty . I also noticed when I unplugged my trailers the tail lights on the truck did not light up. I did run the ground from the T connector and from the 7 way plug to the same bolt . I was wondering If anyone could point me in the right direction , thank you !

asked by: Devin K

Expert Reply:

The first thing to test is the truck's 7-way socket, to make sure that the brake signal for the trailer is making it that far. If you refer to the linked photo of a 7-way socket you will note that the brake circuit is carried on the pin at the 5-o-clock position; ground is at the 7-o-clock position. You will ground your tester, such as # PTW2993, to the ground pin and then apply the tester probe to the brake circuit pin while a helper activates the Prodigy P2's manual override lever with full power and boost selected.

If you detect no signal at the 7-way then move to the truck cab and test the controller's blue output wire for a signal. If there is a signal at the controller but not at the 7-way then the issue is in the wiring between the controller and the 7-way.

Keep in mind that the P2 is a proportional type controller that sends out trailer brake power in proportion to your rate of slowing down. If you are not moving then only the manual override will cause an output signal to leave the controller.

I suggest you also directly test the trailer brakes without connecting it to the vehicle. Use the truck's battery or a well-charged spare battery to apply power directly to the brake circuit on the trailer's plug. A charged battery directly connected like this should cause the brakes to engage. You should hear gentle humming from the brakes.

You may also need to adjust the brake assemblies themselves. Brake pressure in electric drums can be adjusted using a Brake Adjustment Spoon # W80630. Please try these steps and let me know the results.

Your truck's light should not be affected by the trailer being plugged in or unplugged.