E4 displayed; unit may run continuously without forming ice or may shut down on protection.

Safety: Disconnect power and close the water supply valve before servicing.

• Inspect evaporator for heavy ice: Remove the front or top panel and look at the evaporator plate or grid. Thick ice buildup indicates a defrost or cycle timing issue.
• Manual defrost: Allow the unit to sit unplugged with the door open until all ice melts. Place towels to catch water. Do not chip ice with sharp tools to avoid damaging the evaporator.
• Check defrost sensor: Locate the defrost or overfreeze sensor clipped to the evaporator. Inspect for damage and test resistance with a multimeter. Replace if open or out of spec.
• Verify defrost heater (if present): Some Westinghouse models use a small heater to assist ice release. Test the heater element for continuity. Replace the evaporator heater if open.
• Confirm fan operation: Ensure the evaporator fan motor runs freely and moves air across the coil. Poor airflow can cause overfreezing and trigger E4.
• Replace control board if necessary: If sensors and heater are good, the defrost timing or control circuit on the main control PCB may be defective and require replacement.