Excessive frost buildup on the evaporator coil and rear interior panel; airflow is restricted and cooling declines.

Safety: Unplug the freezer before defrosting or testing components. Avoid using sharp tools on ice.

• Manual defrost: Empty the freezer and leave doors open with towels to catch water. Allow all ice to melt completely. This will temporarily restore airflow.
• Test defrost components: With the evaporator exposed, test the defrost heater and defrost thermostat for continuity using a multimeter. Replace any open components.
• Check defrost sensor: Measure resistance of the defrost thermistor and compare to expected NTC values. Replace if open/shorted.
• Control board: If all defrost components test good, the main control board may not be initiating defrost cycles and may need replacement.
• Reassemble and monitor: After repairs, reassemble and monitor for several weeks to ensure frost does not return excessively.