Refrigerator runs constantly and is too cold; food freezing in fresh food section.

Safety first: Disconnect power before accessing sensors or control boards.

Step 1 – Verify actual temperature

• Place a thermometer in the refrigerator and compare to the setpoint.
• If the temperature is significantly lower than set, the control may think it is warm.

Step 2 – Inspect thermistor placement

• Locate the refrigerator thermistor and ensure it is properly clipped in place, not touching the evaporator or light housing.
• Improper placement can cause false readings.

Step 3 – Test thermistor

• Disconnect the thermistor and measure resistance; compare to Sub‑Zero’s chart.
• If resistance is much lower than expected (indicating it “thinks” it is warmer), replace the thermistor.

Step 4 – Check damper and control

• Verify the air damper closes when the setpoint is raised to a warmer temperature.
• If the damper is stuck open or the control board keeps calling for cooling, the damper or control board may need replacement.