Display shows E4; freezer may not defrost and frost accumulates on the evaporator cover.

Safety first: Unplug the freezer before accessing the evaporator or heater. Avoid prying ice with sharp tools to prevent refrigerant leaks.

• Defrost manually: Allow the unit to thaw completely with doors open and towels in place. This will restore cooling temporarily.
• Access heater: Remove the interior back panel to expose the evaporator and defrost heater (often a glass or metal tube at the bottom of the coil).
• Test heater: Disconnect heater leads and measure resistance with a multimeter. An open circuit indicates a failed heater that must be replaced.
• Check defrost thermostat: The thermostat/bi-metal is usually clipped to the evaporator tubing. When cold, it should show continuity. Replace if open when frozen.
• Inspect wiring and connectors: Look for burned or loose connectors in the defrost circuit. Repair or replace as needed.
• Control board: If heater and thermostat test good, the electronic control board may not be sending power to the defrost circuit and may require replacement.