Troubleshooting Brake Controller that Shows False Connection

Updated 08/07/2018 | Published 08/06/2018

Question:

brake box has started staying on and running down battery with no trailer connected and truck off - showing numbers instead of two dots when strailer not connected - showing code 0inch and what looks like the top 1/2 of a 5

asked by: Kim S

Expert Reply:

Sounds like you have a ground somewhere on the brake output circuit of your 7-way wiring. What you need to do first is check the 7-way for any corrosion on the output pin and clean as needed first. Typically when a brake controller is getting a false connection reading the issue is almost always corrosion causing a slight short which confuses the controller into thinking a trailer is connected.

Next check the back of the 7-way for any corrosion or exposed wiring and fix as needed. If the problem persists try cutting the blue wire behind the controller leaving enough wire so that you can reconnect it. If the problem still persists you have a bad controller. If not, then the issue is a short somewhere on the wiring between where the cut was made and the 7-way.

expert reply by: Jameson C