Troubleshooting Curt Venturer Trailer Brake Controller With Brakes Always Locked On

Question:

Ive installed this controller after replacing a Curt triflex in my 77 gmc c35. The triflex had an overload fault on it so I replaced it with a simpler controller. I checked all of my wiring and even replaced the 7way plug on the truck and also the wire for the electric brakes on the truck in case those were the culprit. When I hook up the venturer I am finding the brakes are locked on solid. I cut the wire as you guys explain to and I am finding a full 12 volts at idle on the blue wire of the controller and no voltage on the truck side of the blue wire that is cut. I get voltage when I engage the manual override as well. Do you think I received a bad controller? The included pictures are the voltage at idle from the controller side of the blue wire and also the truck side of the blue wire at idle.

asked by: Chris M

Expert Reply:

The Curt Venturer Trailer Brake Controller # C74VV could be faulty. To find out for sure you can bench test the controller as per the instructions. I have included those below for you to reference.

Before removing it for a bench test I suggest checking the red wire that runs to the brake switch. This should only show 12v power when the brake pedal is pressed. If the brake switch is faulty this would cause the brake controller to believe it needs to send power to the blue brake wire.

To bench test the Controller you will need an 1156 style bulb. The white wire from the controller will connect to the negative battery terminal. The black wire will connect to the positive battery terminal. The blue wire will connect to the 1156 bulb # DI49VR. You will need to run a ground wire from the 1156 bulb to the negative battery terminal as well. Only when you connect the red wire to the positive battery terminal or activate the manual control should the bulb light. The instructions linked below will help you with testing the sync control and output controls as well.

expert reply by: Bud M