A refrigerator thermostat is a device that turns the compressor on and off to maintain the correct temperature inside the appliance. The thermostat is designed to keep the refrigerator's interior between 36 and 45 degrees Fahrenheit. The ideal temperature is 40 degrees.
When the compressor continues to run even after the refrigerator has reached the appropriate temperature, it's possible the thermostat is faulty. If the thermostat shuts off the compressor but the refrigerator still feels too warm, the cause may be a lack of refrigerant, and it must be addressed by a certified repair technician. A refrigerator thermometer can help determine if the thermostat is maintaining the correct temperature.