Troubleshooting Weak Trailer Brakes After Prodigy P2, Wiring, Magnet, and Drum Installation

Question:

Older tandem axle with brakes on rear. 10” drums and new wiring. Installed P2 controller. Brakes were weak right away. Truck running I had 12-13v at the junction box on tongue. 3.2 amps per side. So I installed new loaded backing plates and new drums. Same problem. Verified 12v at backing plates. 3.2 amps per side still. Shoes adjusted out for enough resistance to stop wheel from turning freely still won’t grab. Drove five miles to bed in magnets and shoes. All testing done with manual lever on control at full. Brakes barely grab and just enough to actually notice it in driveway.

asked by: Ben

Helpful Expert Reply:

Since you're getting full power at the actual brakes it doesn't sound like there is an issue with your Tekonsha Prodigy P2 Trailer Brake Controller # 90885. That combined with everything else being replaced makes it sound like a bad ground connection. Double check your ground connections on your brakes and make sure they are secure on a clean, bare metal surface.

The only other possibility is that you need to "break-in" your brakes some more. Especially if they are self-adjusting. Drive the trailer out into an open area, like an empty parking lot. Get up to around 40 MPH and apply the manual override on your brake controller. Do not hit the brake pedal during this time, as you want to slow down your vehicle and trailer with only the trailer brakes. You’ll most likely have to do this about 20 to 30 times to properly seat the brakes. A lot of times it takes more than this to get them properly seated.

I have attached some helpful articles on brake controllers and brake adjustment for your reference.

expert reply by: Robin H