First, make sure that your damper isn't just stuck.  You can gently lift up on the arm and make sure it isn't stuck to the base plate.  From there, with the servo unplugged from the controller, push on the arm to move the damper left and right.

Once the damper is moving freely, plug it back into the controller.  If it moves from fully open to fully closed a couple of times, then it should be working properly.

If it does NOT move when plugged in, then a replacement servo is needed.  You can purchase one here:

If your servo has a sticker on it that says SMOBOT and HiTech, please contact support after placing your oder to ensure you get the new hardware needed to a