Refrigerator displays DF and freezer section may be heavily frosted; airflow is restricted.

Safety first: Disconnect power before testing components.

• Manual defrost: Remove freezer contents and rear panel. If the evaporator is a solid block of ice, allow it to fully defrost (towels and pans to catch water). This will restore temporary cooling.
• Check defrost heater: With a multimeter, test continuity of the defrost heater element. An open reading indicates a failed heater that must be replaced.
• Check defrost thermostat: The thermostat (bi-metal) should show continuity when cold (below freezing). If it is open when cold, replace it.
• Inspect defrost sensor: On many Electrolux models, an NTC thermistor monitors evaporator temperature. If its resistance is out of spec, replace the sensor.
• Control board: If heater, thermostat, and sensor are good but the unit never enters defrost, the main control board may have a failed defrost relay and require replacement.