2011 gmc sierra towing with brakes woes

[Camper3]

I have a 2011 GMC Sierra with a factory tow package. It does have the wiring harness which already had a trailer towing brake system attached but it is not the one that is integrated into the dash. The brake wire is already connected in the fuse box under the hood. My problem is when towing anything with trailer brakes mainly my camper, when I release the brake the brake lights do go out but sometimes they break for the electric brakes on the camper will stay engaged unless I lightly tap the brake pedal. I have changed out the brake switch that mounts on to the brake pedal 2 times and have actually change the brake controller from an F-150 wich still does notresolve anything. I can't imagine the camper is the problem since I have used it with another truck and did not have the same issue and also I've used my father-in-law's car trailer which the brakes would lock up on it as well with using my Sierra. So I'm left with the decision that it's actually the truck. Has anyone had this problem does anybody have any solutions?