12 Volt Power All the Time On Brake Output Circuit with Curt Brake Controller on 1999 Olds Bravada

Updated 03/31/2015 | Published 03/28/2015

Question:

I just finished installing the brake controller and all went according to the instructions. The light on the controller comes on when I press the brake pedal. However, as I was checking the functions of my 7-pin plug I was surprised to find that I got a reading of 12 volts at the brake terminal i.e. blue wire when the brake pedal was not depressed. This is without a trailer attached. Is this correct or how do I know that the brake controller is functioning properly? I am getting ready to travel 400 miles to pick up a new trailer and want to be sure everything is working correctly. Thank-you. My vehicle is a 1999 Oldsmobile Bravada.

asked by: Mitch M

Expert Reply:

There should not be power on the brake output wire unless the brake controller is sending back power. It sounds like something might be miswired at the 7-Way. Take a look at the picture I have included that shows the pin out of a vehicle side 7-Way trailer connector to make sure yours is wired the same way.

If it isn't then put the wires in the appropriate places. Also check to see if any of the wires are touching each other inside the 7-Way. And if the 7-Way is dirty or corroded that could cause a short so make sure it is clean inside and out.

If everything is clean, no wires touching, and all the wires are in the right places then make sure the brake controller white wire is grounded to the negative battery terminal, black to the positive battery terminal via a 20 or 40 amp circuit breaker, red to cold side of brake switch (which we covered previously in another answer), and blue is output to the 7-Way. I have included some links on testing/troubleshooting brake controllers as well.

expert reply by: Michael H