OL Message on Curt Discovery Trailer Brake Controller

Updated 04/10/2019 | Published 04/08/2019

Products Featured in This Question

Curt Discovery NEXT Trailer Brake Controller - Up to 4 Axles - Time Delayed

(59)

$108.95

Curt TriFlex NEXT Trailer Brake Controller - 1 to 4 Axles - Proportional

(981)

$135.95

Question:

Ive had my Discovery Brake controller for a few years, has always worked as advertised. Recently I had the tow vehicle 1998 Chevy Express 3500 van separated from the trailer. The trailer was stored in-doors during this time. When re-connected I get 0, then 0.5inch then OLinch code on the Discovery screen. While not connected to the trailer, the Discovery screen has always been blank as I recall. The contacts on the connector are clean and show no sign of corrosion. I did check all the contacts on the trailer side for tightness and sprayed some WD-40 on them. So the change occurred while disconnected, or its not reconnecting properly. The van was in for some service for a code of being too lean. Not that the lean issue was connected, but maybe they shorted a wire. This seems doubtful as it reads 0.0 and 0.5 before the OL. Any thoughts on what it is?

asked by: Brian L

Expert Reply:

There could be a few different things happening with your Curt Discovery Trailer Brake Controller part # C84VV. The first thing that could be happening is that you have a short on the red stop light switch wire. In order to rule this out you will need to probe the red wire going into the back of the brake controller. There should only be power on this wire with the brake pedal depressed. If there is when it is not then you know there is either a short in this wire or the stop light switch on the vehicle is bad.

The second thing that could be happening is a short on the brake output wire. In order to rule this out you will need to sever the blue wire on the back of the controller, and then test for power. If you do have power without the manual override or brake pedal engaged then there is an internal error inside the brake controller and it will need to be replaced. If you don't have power with the manual override or brake pedal engaged then there is more than likely a short on the brake output wire that leads for the back of the brake controller to the 7-way.

If it turns out that the Curt Discovery Trailer Brake Controller needs replaced then I recommend using the Curt TriFlex Trailer Brake Controller part # C24VV for this because it has proportional operation as opposed to the time-delayed operation of your Discovery and it will use the same wiring harness you already have installed.

I have attached a help article for you as well that explains the benefits of upgrading to a proportional brake controller.

expert reply by: Conner L