Troubleshooting Prodigy P3 Brake Controller that Shorted Out and Blew Vehicle Fuses

Updated 07/05/2019 | Published 07/04/2019

Question:

In a recent question I restated advice given to test a prodigy p3 by touching blunt wire ends of the pigtail to the battery terminals. White to neg, black to positive. I did just that. There was arching at each terminal but the unit did light up. Although this was the anticipated results, I was told the arching would mean a bad unit. My p3 has not been getting power from the truck plug in set up. It worked great on three trips, but now the screen is black. No power at ignition where there was even without the trailer plugged in. So, if Im right that fuses are blowing its difficult to visually see the break can a bad p3 cause the fuse failure, or is something else going on? I can return the unit on warranty, but should I if the test shows it lights up when directly touched to the battery? I need guidance. Thanks

asked by: PAUL A

Expert Reply:

The P3 part # 90195 does not have a reputation for failing and causing the types of problems you are encountering but it's not totally impossible for that to happen. I'd be more inclined to believe that a trailer wiring short caused the brake controller to fail which then caused fuses to blow as the controller then shorted out the vehicle wiring. Again, this is not a common occurrence and the best I can do is speculate from here.

So returning the controller under warranty is the route you'd want to go, but I'd first check all of the brake output wiring on your trailer and vehicle to see if you can find a short and fix this prior so that you don't end up same boat.

expert reply by: Jameson C