E4 error on display, unit may not defrost properly, heavy ice buildup on evaporator

Safety: Unplug the wine cooler. Water and electricity are a dangerous combination; keep the area dry.

• Manual defrost: Open the door and allow all ice to melt. Use towels to absorb water. Do not chip ice with sharp tools to avoid damaging the evaporator.
• Access evaporator and defrost components: Remove the internal rear panel to expose the evaporator coil, defrost heater (if fitted), and defrost sensor.
• Inspect defrost sensor: Look for a small sensor clipped to the evaporator. Check for broken wires or corrosion. Ensure it is firmly attached to the coil.
• Check heater continuity: Disconnect the defrost heater leads and measure resistance with a multimeter. An open circuit indicates a failed heater that must be replaced.
• Test defrost sensor: Measure resistance at room temperature and compare to the Hotpoint NTC chart. Replace if out of specification.
• Inspect wiring and connectors: Follow the heater and sensor wires back to the main control board. Repair any burnt, loose, or corroded connections.
• Replace faulty parts: Install a genuine Hotpoint defrost sensor and/or heater as needed. Ensure all connections are tight and insulated.
• If E4 returns quickly: The defrost control circuit on the main PCB may be defective and require professional replacement.