E3 error on the display; the freezer may not defrost properly, leading to heavy ice build-up on the evaporator and reduced airflow.

Safety: Unplug the freezer before accessing internal panels or wiring. Sharp evaporator fins can cut skin; wear gloves.

• Defrost manually first: Open the door, remove food, and allow the unit to defrost fully (use towels to collect water). Do not use sharp tools to chip away ice.
• Access evaporator area: Remove the rear internal panel in the freezer compartment to expose the evaporator and defrost components.
• Locate the defrost sensor: The sensor is usually clipped to the evaporator tubing or mounted in a small plastic housing attached to the evaporator.
• Check wiring and clips: Look for broken insulation, loose clips, or wires that have been pulled tight and snapped. Ensure the connector to the main harness is secure.
• Test the sensor: With a multimeter, measure resistance at around 0–5°C (use an ice-water bath if needed). Compare the reading to Zanussi NTC charts. Replace the evaporator/defrost sensor if readings are open, shorted, or far from spec.
• Inspect control board: If the sensor is good but the main control PCB does not read it correctly, it may be faulty. Check for visible damage; replacement is usually required if faulty.
• Reassemble and test: Refit the panel, restore power, and monitor for normal defrost cycles over the next 24–48 hours.