Display shows EC3 and unit may not defrost or may shut down due to frost buildup.

Safety: Disconnect power before working near the evaporator or heater.

• Check for heavy frost: Remove interior rear panel and inspect the evaporator. A solid block of ice indicates defrost failure.
• Test defrost heater: Disconnect heater leads and measure resistance with a multimeter. An open circuit indicates a failed heater that must be replaced.
• Inspect defrost thermostat/thermal fuse: Locate the thermostat clipped to the evaporator tubing. Test continuity when the thermostat is cold (below its closing temperature). Replace if open when cold.
• Check wiring and connectors: Inspect the harness from heater and thermostat back to the control board for burns, loose connections, or breaks.
• If heater and thermostat test good: The defrost relay or logic on the main control board may be faulty. Replacement of the main control board is typically required.
• Manual defrost: As a temporary measure, allow the unit to defrost fully by unplugging and leaving the door open with towels to catch water. Do not use sharp tools to chip ice.