Display shows E3 and the defrost cycle does not operate correctly (excessive ice on evaporator).

Safety: Unplug the wine cooler. Allow any ice to melt naturally; place towels to catch water. Avoid using sharp tools to remove ice.

• Access evaporator and defrost components: Remove interior rear panel to expose the evaporator, defrost heater, and defrost sensor.
• Inspect defrost sensor: The defrost NTC is usually clipped to the evaporator tubing. Check for broken wires or a sensor that has come loose.
• Test defrost sensor: Measure resistance at freezer temperature (after cooling) and at room temperature. If readings are open, shorted, or do not change, replace the sensor.
• Check defrost heater: Visually inspect the heater element for breaks or burn marks. Test continuity with a multimeter; an open circuit indicates a failed heater.
• Inspect wiring and connectors: Verify all connectors between heater, sensor, and PCB are secure and not corroded.
• Replace faulty parts: Install a new Grundig defrost NTC sensor and/or Grundig defrost heater as required. Ensure proper positioning on the evaporator.
• PCB evaluation: If heater and sensor test good, the defrost relay or control logic on the main PCB may be defective and the board should be replaced.