Our trailer brakes are essentially useless. When the brake is applied lightly the trailer brake increases until it locks. If the brake controller is adjusted to the proper level this causes the trailer brakes to lock up and jerk free when released. It does not apply proportionally to the amount of pressure applied to the truck brake. Adjusting the controller down does not fix the problem as it only resolves when the level to low enough where essentially no braking is applied to the trailer.
This occurs in every trailer we haul (horse trailer, dump trailer and flatbed trailer). All trailer function appropriately when hooked up to other trucks. We have had the brake controller changed and an additional new controller tested within the same results. All trailer brakes have been inspected and are wiring appropriately. Trailer plug outlets have been replaced.
This has been looked at by several mechanics and trailer shops without any luck identifying the problem.
Truck is a 2003 Chevy 3500 dually. Current brake controller is a Curt brand.
