Refrigerator display shows F05, unit may run continuously or not defrost properly, heavy ice on evaporator.

Safety first: Unplug the refrigerator before accessing the evaporator area.

Step-by-step checks:

• 1. Access evaporator area: Remove freezer drawers and inner rear panel to expose the evaporator coil and defrost components.
• 2. Locate defrost NTC: The defrost sensor is usually clipped directly to the evaporator tubing or attached with a metal clip or tie.
• 3. Check physical contact: Ensure the sensor is firmly touching the evaporator coil. If it has fallen away, reattach it securely; poor contact can cause incorrect readings.
• 4. Test resistance: Disconnect the sensor and measure resistance with a multimeter. Compare to the expected NTC curve. If open or shorted, replace the sensor.
• 5. Inspect wiring: Follow the sensor wires back to the harness connector. Look for cuts, pinches, or corrosion. Repair or replace damaged sections.

When to call a technician: If a new sensor does not clear F05, the control board may have a defective sensor input and require professional diagnosis.