Galanz freezer shows E3 and interior temperature fluctuates or defrost seems irregular.

Safety: Unplug the freezer before accessing the evaporator or control board. Avoid touching bare metal with wet hands.

• Access defrost sensor: Remove food and shelves, then take off the rear interior panel to expose the evaporator. The defrost sensor is often clipped to the evaporator tubing or attached near the defrost heater.
• Visual inspection: Look for a small plastic-encased sensor with two wires. Check for cracked casing, melted plastic, or wires damaged by ice or heater heat.
• Check wiring: Follow the sensor wires to the connector. Ensure the connector is fully seated and free of corrosion. Repair any obvious breaks with proper crimp connectors and heat-shrink tubing.
• Test the sensor: Disconnect the sensor and measure resistance with a multimeter. At freezer temperatures, resistance should be significantly higher than at room temperature. If it reads open or shorted, it is defective.
• Replace the sensor: Install a new Galanz defrost sensor / thermistor. Clip it in the same location and orientation as the original to ensure proper defrost control.
• Control board evaluation: If the sensor tests good but E3 persists, inspect the main control board (usually behind a rear metal cover). Reseat the defrost sensor connector. If the board is visibly damaged or the error will not clear, replacement of the board is likely required.
• Reassemble and test: Reinstall the evaporator cover, restore power, and allow 24 hours of normal operation to confirm proper defrosting and that E3 does not return.