Display shows E3; defrost cycles may be too frequent or not occurring, leading to frost buildup or temperature swings.

Safety first: Unplug the refrigerator before removing the freezer rear panel. Evaporator fins are sharp; wear gloves.

• Access the evaporator: Remove freezer shelves and the rear interior panel to expose the evaporator coil and defrost components.
• Locate defrost thermistor: It is usually clipped to the evaporator tubing. Ensure it is firmly attached and not hanging loose.
• Inspect wiring: Look for brittle, cracked, or broken wires leading from the thermistor to the harness connector.
• Test thermistor: With the sensor at room temperature, measure resistance and compare to the expected NTC curve (often ~2.7–3.5 kΩ at 77°F). Replace if open, shorted, or far out of spec.
• Reattach properly: Clip the new defrost thermistor securely to the evaporator tubing in the same location to ensure accurate sensing.
• Control board: If the E3 code remains after replacing the thermistor and verifying wiring, the main control board may not be reading the sensor correctly and should be evaluated by a technician.