Troubleshooting Brake Controller that is Showing Brake Output on Display When Vehicle is Off

Question:

All winter my trailer was in storage. As I drove around in my 2010 Highlander, the number on the display would go higher when I applied brakes. When the car was off and I walked by, I could see 2.5 on the readout. Any ideas? Thank you for considering my question.

asked by: Matt M

Expert Reply:

Sounds like there's a short between the power wire of the P2 part # 90885 (black wire) and the stoplight circuit wire (red wire). When there's power on the red wire the controller thinks the vehicle's brakes are applying and that it needs to start applying the trailer brakes. So if you check the wiring between those two circuits and clean up any shorts the problem will go away.

expert reply by: Jameson C