This sensor (Temperature Sensor, Thermistor, Refrigerator Temperature Sensor) sends the temperature reading of the compartment to the control board. If you notice your refrigerator is too warm, too cold, or not defrosting properly, then there may be a problem with your sensor. The temperature sensor can break from material fatigue or through normal use, and should be replaced. It is attached to the evaporator and control housing in your appliance.