Freezer shows E3 and may not defrost properly; heavy frost builds up on the evaporator and airflow is reduced.

Safety: Disconnect power before accessing the evaporator area. Sharp freezers have sharp metal edges and live wiring behind panels.

Steps to diagnose and fix:

• Access the evaporator: Empty the freezer section as needed. Remove the rear interior panel (usually held by screws and clips). If there is heavy ice, allow it to melt with the unit unplugged; do not chip ice with sharp tools.
• Locate the defrost sensor: The defrost thermistor is typically clipped to the evaporator tubing or attached with a metal clip or plastic holder near the top or middle of the coil.
• Check mounting: Ensure the sensor is firmly attached to the coil. A loose sensor can misread temperature and trigger E3. Re-clip or secure it in the original position.
• Test the sensor: Disconnect the thermistor from its connector. Measure resistance at room temperature and again after briefly cooling it with an ice pack. Resistance should increase smoothly as temperature drops. If it reads open, shorted, or does not change with temperature, replace it.
• Inspect wiring: Follow the sensor wires back to the harness and main PCB. Look for brittle insulation, corrosion at connectors, or pinched sections where panels attach. Repair or replace damaged wiring.
• Control board evaluation: If a new sensor and good wiring still result in E3, the main control PCB may not be reading the defrost sensor correctly. Replacement of the PCB is indicated.

Finalization: Reassemble the evaporator cover, ensuring no wires are trapped. Restore power and allow the freezer to run through at least one defrost cycle (often 8–12 hours) to confirm that frost buildup is controlled and E3 does not return.