Troubleshooting Brake Controller Installation in 2001 Chevrolet Silverado

Updated 03/25/2016 | Published 03/23/2016

Question:

Why does the trailer have full power from the break controller . Even after we installed three different controllers?

asked by: Alfred G

Expert Reply:

A common cause for a trailer brake circuit to activate at full power is a corrosion issue in the vehicle 7-way socket and/or the trailer plug. Corrosion can build-up inside a connector or on its contacts. When this happens two separate circuits, like the brake circuit and the 12V trailer power circuit, can become bridged together. This would result in the always-on 12V circuit bleeding into the brake circuit which would result in full power reaching the electric brakes all the time.

The first thing to do is check the condition of both socket and plug, both externally and internally if possible, to remove any corrosion. If badly deteriorated you might need to replace the vehicle socket and trailer plug.

Another potential cause is that the wiring adapter # 3025-P that connects to the under-dash port on your truck is mis-wired. This is rare but it can happen. Make sure your harness' vehicle end plug is wired like the photo I linked. If this were the problem it would occur with every controller you use.

expert reply by: Adam R