Wine cooler beeps and shows E4; unit may shut down or run erratically.

Safety: Unplug the cooler. Be cautious of sharp fins on the evaporator and any remaining ice.

• Defrost completely: Allow the unit to thaw fully with the door open. This makes it easier to access components and prevents water from dripping onto electrical parts during service.
• Access evaporator and defrost components: Remove the interior rear panel to expose the evaporator coil. Locate the defrost thermistor (often clipped to the coil) and the defrost heater (a tube or wire element at the bottom or around the coil).
• Visual inspection: Look for burnt or broken heater elements, disconnected wires, or a thermistor that has come loose from the coil.
• Test the defrost heater: With the unit unplugged, disconnect the heater leads and measure resistance. A typical heater will show some resistance (e.g., 50–300 ohms). Infinite resistance indicates an open heater that must be replaced.
• Test the defrost thermistor: Measure resistance and compare to other thermistors in the unit at similar temperature. An open or shorted reading indicates a bad sensor.
• Check wiring to control board: Inspect the harness from the evaporator area to the main control board for pinched or corroded wires.
• Replace faulty parts: Install an OEM Avanti defrost heater or defrost thermistor as needed. Ensure all connections are tight and insulated.
• Control board consideration: If heater and sensor test good but E4 persists, the defrost relay or logic on the control board may be defective and the board will need replacement.