Display shows E4 and the compressor or cooling module may not run correctly; unit may shut down prematurely.

Safety: Disconnect power before removing interior panels or working near the evaporator.

• Access evaporator area: Inside the cooler, remove shelves and the rear interior panel (often clipped or screwed) to expose the evaporator coil.
• Locate sensor: Find the small NTC sensor clipped or taped to the evaporator tubing. Ensure it is firmly attached and not hanging loose.
• Inspect wiring: Look for brittle, cracked, or iced-over wiring. If insulation is damaged, replace the sensor assembly rather than attempting to tape over bare wires.
• Check connector: From the rear of the unit, follow the sensor wires to the main control PCB and reseat the connector.
• Test sensor: With a multimeter, measure resistance at room temperature and compare to cabinet sensor values. A reading of open circuit or near zero indicates failure. Replace with a compatible evaporator NTC sensor.
• Reattach correctly: Clip or tape the new sensor firmly to the evaporator tube in the same position as the original to ensure accurate defrost control.
• Persistent E4: If the sensor and wiring are good, the PCB defrost circuit may be defective. PCB replacement is a level‑5 repair and should be done by a professional.