Freezer shows F04 and may not defrost properly, leading to ice buildup on the evaporator.

Safety first: Unplug the freezer and allow any ice to soften before working near the evaporator.

Access the defrost components:

• Remove drawers and the internal rear panel to expose the evaporator assembly.
• Locate the defrost thermostat or thermal fuse clipped to the evaporator tubing, and any separate defrost NTC sensor.

Testing:

• With a multimeter, test continuity across the defrost thermostat/thermal fuse at room temperature. It should show continuity; an open reading indicates it has tripped or failed.
• Measure resistance of any defrost NTC sensor and compare with expected NTC values.
• Inspect wiring for signs of overheating or brittle insulation near the defrost heater.

Repair:

• Replace any open defrost thermostat or thermal fuse with the correct Indesit-rated part (temperature and current rating must match).
• If the defrost NTC is faulty, replace it and secure it back in the original position on the evaporator.
• Check that the defrost heater is not visibly damaged or warped; if it is, replace the heater as well to prevent repeat failure.