Freezer not maintaining set temperature, F04 error on display, frequent high-temperature alarms.

Safety first: Disconnect mains power before removing freezer panels.

Step-by-step checks:

• 1. Access the freezer NTC: Remove freezer drawers and the rear inner panel. The NTC is usually clipped to the evaporator tubing or mounted in a small well near the evaporator.
• 2. Inspect sensor and clip: Ensure the sensor is firmly attached to the evaporator or in its pocket. A loose sensor can misread temperature and trigger F04.
• 3. Measure resistance: With the appliance off, disconnect the sensor and measure resistance. Compare to expected values for the approximate freezer temperature (e.g., at 0°C many NTCs are around 12–30 kΩ). Out-of-range readings indicate a faulty sensor.
• 4. Replace the sensor: If faulty, install a new Indesit freezer NTC probe. Clip it securely to the evaporator or into its holder to ensure accurate sensing.
• 5. Check for moisture ingress: Look for water or ice around the sensor connector. Dry thoroughly and ensure connectors are tight.

When to call a technician: If the sensor and wiring are intact but the control still reports F04, the main PCB or its input circuitry may be defective.