Freezer displays E4 and may not defrost properly; ice accumulates on evaporator and airflow is reduced.

Safety: Unplug the freezer and be cautious around sharp metal edges and ice.

E4 indicates a problem in the defrost circuit.

• Access evaporator: Remove freezer contents and the rear interior panel to expose the evaporator coil and defrost components.
• Inspect heater: The defrost heater is usually a metal or glass-encased element at the bottom or woven through the evaporator. Look for breaks, burn marks, or discoloration.
• Check continuity: With the unit unplugged, disconnect the heater leads and test with a multimeter. A good heater shows continuity (low resistance). Replace if open.
• Check defrost thermostat/fuse: Locate the defrost thermostat or thermal fuse clipped to the evaporator tubing. Test for continuity when cold (in ice water). Replace if open.
• Inspect wiring and connectors: Follow the harness from the heater and thermostat to the main board. Repair any burnt, loose, or corroded connections.
• Manual defrost: If heavily iced, fully defrost the evaporator before reassembly to restore airflow.

If heater and thermostat are good, the main control board’s defrost relay or triac may be defective and typically requires professional replacement.