I have figured out the damper is not working properly. The temperature in the fresh food compartment is less than control setting yet the damper was still open and allowing cold air to enter the compartment. The only way to close the damper was to manually hold the damper door up. The knob on the side of the box does rotates on its own power when the door is held up to provide clearance. Now the question is how do I figure out which of the many possible parts (e.g, the control harness,the damper control assembly etc) is causing the problem. I really don't want to go through a process of elimination since I don't have the time or money. Your help would be much appreciated. Thanks

Edit: The damper is working for opening the door when the frig temp exceed the 38 degree setting but doesn't close when the compartment set temperature is reached but continues remain open and let cold air in indefinitely.