Freezer temperature fluctuates widely after defrost cycle; food partially thaws then refreezes.

Safety first: Unplug the freezer before accessing the evaporator or control board.

• Monitor pattern: Note if temperature spikes occur at regular intervals corresponding to defrost cycles.
• Inspect defrost components: Access the evaporator and check the defrost heater, thermostat, and NTC sensor for correct mounting and condition.
• Test defrost thermostat: If fitted, it should open at a specific temperature to stop heating. Test continuity in ice water and at room temperature; replace if stuck closed.
• Check sensor readings: Verify the evaporator NTC sensor resistance at known temperatures; replace if out of spec.
• Replace main control board: If hardware is good but defrost duration is excessive, the control board may be mismanaging defrost and should be replaced.

Warning: Excessive warming during defrost can compromise food safety; address promptly.