Safety first: Unplug the freezer before accessing the evaporator and electrical components. Water from melting ice can create slip hazards.

1. Manual defrost: Remove drawers, unplug the unit, and allow all ice on the rear panel to melt completely. Use towels to collect water.
2. Access evaporator: Remove the rear inner panel to expose the evaporator coil, defrost heater, and sensors.
3. Test heater and sensors: With a multimeter, check continuity of the defrost heater and thermal fuse, and measure resistance of the defrost sensor. Replace any open or out-of-spec components with SMEG parts.
4. Inspect wiring: Look for broken or corroded wires between the evaporator area and the main PCB.
5. Control board: If all components test good, the defrost control function on the main PCB may be defective and require replacement by a technician.
6. Reassemble and monitor: After repairs, reassemble panels, restore power, and monitor for several days to ensure frost does not reaccumulate.

Thick ice buildup on the rear interior panel and poor cooling in the rest of the freezer.

Possible Causes