Updated: Apr 15
If your RS21 fridge evaporator defrost sensor has failed you will find an ice build up at the rear of the evaporator cover, similar to the image below
Buy GENUINE Samsung defrost sensors direct from us here...
This image shows the fridge evaporator severely iced up due to failure of the evaporator defrost sensor, part number DA32-00006W. You may consider replacing part number DA47-00095E - thermal fuse. The thermal fuse can fail as a result of the defrost sensor failure. If you have no means to test the circuits of these components, we would recommend you purchase these parts as a
service kit to include DA32-00006W and DA47-00095E