Why Would a Trailer Brake Controller Have a SC Error Only When Put Into Drive?

Updated 06/09/2024 | Published 06/02/2024

Question:

I installed a Hopkins agility trailer brake controller with the correct Hopkins wiring harness on my 03 excursion XLT. Trailer brakes work in 1,2 and R. But, when I put it in drive, I get a short circuit flashing on my unit. I have checked the connections multiple times. Any thoughts?

asked by: Ben

Expert Reply:

This one has me stumped Ben. Your Hopkins Agility just like other brake controllers ties into a power, ground, the brake switch and has the output for the trailer brakes. There is nothing connecting to a gear position/neutral switch so it makes no sense why it would only show the SC error when put into drive and not 1,2 or R. The only thing I can think is there is some kind of short in the factory wiring which is causing the issue you are having. This may be difficult to find due to the position of all the wiring up under the dash.

expert reply by: Bud M