Wine cooler displays E4 and may stop cooling or run continuously with poor temperature control.

Safety first: Unplug the wine cooler before accessing internal panels. Beware of sharp metal and possible ice buildup.

Steps to address E4:

• Defrost the unit: Leave the door open with the unit unplugged for several hours to melt any ice on the evaporator. Place towels to catch water. After defrosting, reconnect power and check if E4 returns.
• Access evaporator and defrost components: Remove internal rear panel to expose the evaporator coil. Locate the defrost sensor (often combined with the evaporator sensor) and the defrost heater (a tube or wire element attached to the evaporator).
• Inspect wiring: Look for burnt, broken, or disconnected wires around the heater and sensor. Repair any obvious damage using proper insulated connectors.
• Test defrost heater: With the unit unplugged, disconnect heater leads and measure resistance. A typical heater will show a finite resistance (e.g., 50–300 Ω). An open circuit indicates a failed heater.
• Test defrost sensor: Measure resistance of the defrost sensor/NTC at room temperature and compare to specifications. Replace if open, shorted, or out of range.
• Replace faulty parts: Install a Hoover-compatible defrost heater or defrost sensor as needed. Ensure good thermal contact with the evaporator and secure wiring away from sharp edges.
• PCB diagnosis: If heater and sensor test good but E4 persists, the defrost relay or control circuit on the main PCB may be defective and require board replacement by a technician.