Display shows E5 and the refrigerator may not defrost or may trip thermal protection.

Critical safety warning: The defrost heater operates at mains voltage and can become very hot. Unplug the refrigerator before testing. Do not touch the heater when energized.

Diagnostic steps:

• 1. Inspect for frost buildup: Heavy ice on the evaporator cover or back wall indicates defrost failure.
• 2. Access heater assembly: Remove freezer drawers and the rear panel to expose the evaporator and heater. The heater is usually a glass or metal tube at the bottom or woven through the evaporator.
• 3. Visual check: Look for burned spots, broken heater tube, or melted connectors. Check the defrost thermostat/thermal fuse mounted on the evaporator tubing.
• 4. Test heater resistance: With power disconnected, unplug the heater leads and measure resistance. Typical values are 50–300 Ω depending on model. An open circuit (OL) indicates a failed heater.
• 5. Test defrost thermostat/fuse: At freezer temperature, the thermostat should read near 0 Ω (closed). If it is open when cold, it is faulty. Some Haier models use a one-shot thermal fuse that must be replaced if open.
• 6. Check wiring and PCB: If heater and thermostat test good, inspect wiring to the main PCB and the defrost relay on the board. Burned or loose connectors must be repaired. A failed relay or PCB will require board replacement.
• 7. Replace failed components: Install a new Haier-compatible defrost heater and/or thermostat/thermal fuse as needed. Secure all parts firmly and keep wires away from hot surfaces.

Note: After repair, fully defrost the evaporator before restarting to avoid immediate re-icing.