Should I Always Have Power On Blue Wire After Installing Curt TriFlex Trailer Brake Controller


The problem I am having is after installation of brake controller. I tested the seven way to make sure all was functioning correctly with a seven way tester with lights indicating the function. When I plug in the tester the break function is illuminated like I have my foot on the pedal. I disconnected the blue wire from Brake controller it went away. My question is when I hook to my trailer are my brakes going to lock up? Curt Triflex brake controller I have checked all my wiring it is correct. When brake Pressed it activates the controller like normal. I also checked for shorts. It’s all new wiring. Will not be connecting to a trailer at this time so I would like to know if there is a problem with the unit or if that’s the way it works?


Expert Reply:

The only time you want to see power on the blue brake wire from the Curt Triflex Brake Controller part # C51140 is when the brake pedal depressed in the vehicle or the brake controller manual override is activated. If the blue wire has a constant 12V then it is an indication that there is an issue with the wiring. This could lead to your trailer brakes locking up, getting hot or not working at all once you hook your trailer up.

I was able to find your account and it looks like you used the universal installation kit part # C57186. I recommend to make sure the red wire is properly connected to the cold side of the brake switch in your vehicle. You want the brake controller to be activated by the vehicle brakes only when the brakes are depressed so the red wire needs to be connected to the wire near the brake pedal that only shows power when you press the brake.

You may also consider checking that the ground is sufficient on the brake controller and the 7-way plug. The ground of the plug needs to be attached to a clean bare metal surface on the vehicle. If the brake controller is hardwired the white wire from the brake controller needs to be grounded to the vehicle's battery. I have attached a diagram for your reference.

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expert reply by:
Heather A

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