Curt Venturer Brake Control Applies Full Power to Trailer Brakes All the Time on 2000 GMC Sierra


I installed a venturer controller on my 2000 GMC Sierra 1500 with the pigtail ordered specifically for the vehicle. I have used it on several trailers and I connot seem to get it set correctly. When applying brake, it locks the trailor brakes solid. I have adjusted the output between 1 and 3 bars, and set the sync to the least agressive setting. Is there something else I can try to make it work correctly? Thanks for your time.


Expert Reply:

The first thing to check is the wiring harness # C51342 for your 2000 GMC Sierra. Specifically, check the location of the red wire on the end that plugs into the truck. Make sure it is in the same location as the one in the picture. If not, or if any of the wires are in different locations, move them to the correct locations according to the picture.

Make sure the controller is mounted within the range specified in the instructions, linked to the right for reference. If it is outside of that range, even if the sync and output are all set properly, you can experience all sorts of issues including what you are describing. On this controller, I would try to have it as level as possible and not at any extreme angles.

Curt says that the controller can be slightly tilted or turned to one side. However, it should really be as straight as possible in the direction of travel.

If none of that helps then you can test the controller to see if it has an internal problem. In the truck cab you will need to sever the blue wire several inches from the back of the controller. Then use a circuit tester such as # 40376 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override. If it shows power at idle then there is something wrong with the controller and it will need to be replaced.

If it tests fine then reconnect the blue wire. Then move on to the truck side trailer connector. Many times, dirt or corrosion can cause a short in a trailer connector. Make sure the truck and the trailer side connectors are clean and free of corrosion inside and out.

You can test the brake output pin and it should only show power with the manual override. If it shows power any other time then there is a short somewhere between the connector and the brake controller you will need to track down. I have included some links to the right that explain testing and troubleshooting for you.

The other issue is that if your truck is a C/K series and not an actual Sierra then the plug in harness will not work. The controller has to be hardwired in. 2000 was a split year. Some models were C/K series which might have included a Sierra trim but they weren't called Sierras, and then there was the actual Sierra which became the name of the truck and continues to this day.

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expert reply by:
Michael H

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