Vegetables in fruit and vegetable bin is freezing.

Cleaned under and back of fridge and took off plate in back. Replaced filter pad and water line. Has always made ice but water dispenser does not work. If I use a hair dyer on warm setting to blow air onto coil behind vegetable/fruit bins water will flow but stops within an hour. One time I could hear the water freezing and stopping. The hair dryer was a "solution" a repairman used to have water flow. Of course he was not there an hour later. Second repairman replaced a part (nothing stated on receipt) and fridge still freezes and dispenser does not flow. Could the damper not be closing properly? Saw posting on another website. Cleaned under and back of fridge and took off plate in back. Replaced filter pad and water line. Has always made ice but water dispenser does not work. If I use a hair dyer on warm setting to blow air onto coil behind vegetable/fruit bins water will flow but stops within an hour. One time I could hear the water freezing and stopping. The hair dryer was a "solution" a repairman used to have water flow. Of course he was not there an hour later. Second repairman replaced a part (nothing stated on receipt) and fridge still freezes and dispenser does not flow. Could the damper not be closing properly? Saw posting on another website.