Wine cooler shows E4 and may stop cooling or run erratically; defrost cycles may not occur correctly.

Safety first: Disconnect power before accessing the evaporator or control board. The defrost heater and wiring can be live and hot during operation.

E4 is commonly associated with defrost system issues in Café wine coolers.

• Step 1 – Check for heavy frost: Open the cabinet and inspect the rear interior wall. If there is a thick sheet of frost or ice, the defrost system is likely not working.
• Step 2 – Access evaporator and defrost components: Remove shelves and the rear interior panel to expose the evaporator coil. Locate the defrost heater (usually a tube or wire element under or around the coil) and the defrost sensor/thermistor clipped to the coil.
• Step 3 – Test defrost sensor: With the unit unplugged, disconnect the defrost sensor and measure resistance. Compare to Café specifications at the current coil temperature. Replace if open, shorted, or out of range.
• Step 4 – Test defrost heater: Disconnect heater leads and check continuity with a multimeter. An open circuit indicates a failed heater that must be replaced.
• Step 5 – Inspect wiring and board: Check the harness from the heater and sensor back to the main control board for burns, loose connectors, or broken wires. If both heater and sensor test good, the defrost relay or control logic on the main control board may be defective and require board replacement.
• Step 6 – Manual defrost (temporary): As a temporary measure, you can defrost the evaporator by unplugging the unit and leaving the door open for several hours, placing towels to catch water. Do not use sharp tools to chip ice.

Persistent E4 after component replacement should be evaluated by a professional technician.