Display shows E4 and the wine cooler may not defrost properly or may ice up around the evaporator.

Safety warning: Disconnect power before working inside the cabinet or rear compartment. Avoid contact with sharp evaporator fins.

• 1. Inspect for heavy frost: Remove interior rear panel and check the evaporator. If it is encased in ice, the defrost system is likely not working.
• 2. Locate defrost thermistor: It is usually clipped to the evaporator tubing. Check that it is firmly attached and not dangling.
• 3. Test defrost thermistor: With the unit unplugged, disconnect the thermistor and measure resistance. Compare to the expected NTC values at the current temperature. Replace if open, shorted, or out of range.
• 4. Check defrost heater: Locate the defrost heater element at the base or around the evaporator. Disconnect one lead and measure resistance. A typical heater will show finite resistance (often 50–300Ω). If it reads open (OL), replace the defrost heater.
• 5. Inspect wiring and control board: Verify continuity from the heater and thermistor back to the main control board. If wiring is intact and components test good, the defrost relay or control logic on the board may be faulty. Replace the main control board if it is not energizing the heater during defrost.
• 6. Manual defrost: While waiting for parts, you can manually defrost by unplugging the unit, opening the door, and allowing ice to melt. Protect the floor from water. Do not use sharp tools to chip ice.
• 7. Reassemble and test: After replacing faulty parts, reassemble panels, restore power, and monitor for several days to ensure frost does not build up and E4 does not return.