Curt Discovery Trailer Brake Controller # C84VV Displays Only a Red Dot After Installation

Updated 06/12/2015 | Published 06/11/2015

Question:

I wired the curt discovery in my 11 Silverado and all I get is a red dot

asked by: Greg J

Expert Reply:

If your Curt Discovery Trailer Brake Controller # C84VV displays only a red dot when you do NOT have a trailer connected then this indicates that the controller's red (input signal) wire is connected to the wrong side of the brake light switch. This red wire should connect to the COLD side of the switch that has power only when you press the brake pedal.

If your Discovery displays the red dot when you DO have a trailer connected then this usually indicates a problem in the trailer brake circuit wiring. In this case the controller cannot "see" the trailer brake magnets.

Check both your vehicle and trailer connectors for discolored, corroded or bent contacts on the brake circuit pins. Clean or repair as needed. Check that the vehicle and trailer main harness ground wires are solidly attached to a clean bare metal surface. You can also check the brake wiring itself to make sure that each brake assembly is properly grounded to the trailer frame.

If none of these checks reveal the problem you can also test your brakes directly by applying power from a spare battery direct to the contacts on the trailer's plug. If your brakes engage fully (as they should when you hit them with a full 12 volts) then you can move on to the truck wiring as the likely source for the problem.

expert reply by: Adam R