Display shows E3 and the refrigerator struggles to maintain set temperature; fan may run continuously.

Safety first: Disconnect the appliance from mains before removing freezer panels.

Steps:

• Access evaporator assembly: Remove freezer drawers and the rear inner panel to expose the evaporator coil and wiring harness.
• Locate defrost sensor and fuse: The evaporator NTC sensor is usually clipped to the evaporator tubing. A defrost thermal fuse may be taped or clipped to the coil or wiring bundle.
• Check for heavy frost: If the evaporator is completely iced over, defrost the unit fully by unplugging and leaving doors open. This may temporarily restore operation but does not fix a failed sensor/fuse.
• Test components: With a multimeter, check continuity of the thermal fuse (should read close to 0 Ω). Check resistance of the evaporator NTC sensor (should be in kΩ range, not open or shorted).
• Replace faulty parts: If the fuse is open, replace it with the correct Etna defrost thermal fuse. If the sensor is out of spec, replace with an Etna evaporator NTC sensor. Do not bypass the thermal fuse.
• Reassemble and test: Reinstall the rear panel, restore power, and monitor if the E3 code clears after a defrost cycle.