The refrigerator shows 'F10' or a similar defrost sensor error, causing intermittent cooling and ice on the evaporator.

Safety first: Disconnect mains power before working inside the cabinet.

Steps:

• 1. Access evaporator area: Remove drawers and the rear interior panel to expose the evaporator and attached components.
• 2. Locate defrost sensor: The evaporator NTC is typically clipped to the evaporator tubing or embedded in a small housing attached to the coil.
• 3. Check positioning: Ensure the sensor is firmly attached to the coil; if it has fallen away, reclip it in the correct position.
• 4. Inspect wiring: Look for damaged insulation, stretched wires, or corroded connectors leading back to the main control board.
• 5. Test sensor (advanced): Disconnect the sensor and measure its resistance at a known temperature. Compare it to V-ZUG specifications. An open or shorted reading indicates failure.
• 6. Replace sensor: Install the correct V-ZUG evaporator/defrost NTC sensor, routing the cable as it was originally to avoid contact with sharp metal or moving parts.
• 7. Clear ice and reassemble: Fully defrost any remaining ice, then reassemble the panels and restore power. Monitor for recurrence of F10.

Warning: Avoid bending evaporator tubes; they are thin and can be punctured easily.