Troubleshooting Pilot Trailer Brake Controller with .c Displayed All the Time

Question:

Says .c all the time regardless if connected or not reads 0.1 while pressing the brakes its not functioning properly

asked by: Daniel

Expert Reply:

It sounds like there may be a short somewhere on the vehicle's brake output circuit. The ".c" that is constantly being displayed on the Pilot Brake Controller # 80550 indicates that it is sensing a connection to a trailer, even when there isn't actually a trailer hooked up. The short is putting a slight load on the circuit at all times that is telling the controller there is a connection. This is also consistent with the low output reading you are getting on the display when hitting the brakes.

I recommend inspecting the 7-Way connector on both the vehicle and trailer side, looking for any debris or corrosion around the pins that need to be cleaned out.

If this looks fine then you can also do a quick test to make sure the brake controller itself isn't damaged, especially if it is an older unit. You will just want to sever the blue brake output wire leaving the controller (leaving enough room to reconnect it). If after doing this the controller still reads ".c" then you know the issue is an internal short on the controller and it will need to be replaced.

Please let me know if you still aren't able to locate what is causing the issue and we can continue to troubleshoot.

expert reply by: Chris R