Costway upright freezer shows E3 and the compressor cycles erratically or not at all.

Safety: Unplug the freezer before removing any exterior panels or touching wiring. Do not bypass sensors permanently.

How to troubleshoot E3:

• Locate the ambient sensor: On many Costway freezers, the ambient sensor is located near the front control panel or behind the top/front plastic trim, sensing room temperature.
• Remove control panel cover: Use a screwdriver to remove screws holding the display/control housing. Carefully pull it forward to access the wiring.
• Identify the sensor: Look for a small probe or plastic-encased sensor with two wires leading to the main board or display board.
• Inspect wiring: Check for pinched, cut, or disconnected wires. Ensure the connector is firmly seated on the board.
• Test the sensor: Disconnect the sensor and measure resistance at room temperature. Compare to typical NTC values (often 5–20 kΩ at ~25°C). If reading is 0 Ω or OL, the sensor is defective.
• Replace if needed: Install a compatible Costway ambient NTC sensor. Route the wires away from sharp edges and hot components, and secure with clips or tape.
• Reassemble and test: Reinstall the control panel, restore power, and verify that E3 clears and the compressor cycles normally over several hours.

Call a technician if: The sensor tests good but E3 remains, which may indicate a faulty display/control board.