This SxS reefer evaporator was heavily frosted. The evap. fan cycles on and off every few seconds. The defrost heater is not open. The heater gets hot when fridge is placed in defrost mode. The evaporator fan motor and terminator were replaced. Same problem few days later. The damper motor was grinding so it was replaced. The only remaining item is the ADC board which has not been replaced yet. There is nothing else left! Any suggestions would be appreciated.