Top freezer Whirlpool refrigerator model # WRT519 was freezing all the food in the fresh food section. I am a tech and I made a mistake before by not knowing about this issue. This unit has two sensor, one in fresh food section and another one in freezer section. Air damper is pretty much doesn’t exist in this model so when it gets low on Freon, sensor in the freezer does not detect freezing temperature and also sensor in the freezer is located at the end of the evaporator coil. Refrigerator keeps running, freezer won’t get freezing cold but fresh food section gets super cold.