Display shows E4 and the unit may run continuously or not defrost properly, with ice buildup on the evaporator.

Safety: Unplug the cooler and allow any ice to melt before working near the evaporator.

• Defrost first: Leave the door open and place towels to catch water. Let the unit sit unplugged until the evaporator area is free of ice.
• Access evaporator: Remove the interior rear panel in the affected zone to expose the evaporator coil and sensor.
• Inspect sensor: Locate the small probe clipped to the evaporator tubing. Check if it is broken, corroded, or has pulled away from the coil.
• Test sensor: Use a multimeter to measure resistance at room temperature. Replace if open or shorted.
• Install new sensor: Clip the new TYLZA-compatible evaporator sensor firmly to the coil in the original position to ensure accurate defrost sensing.
• Reassemble and test: Refit the panel, restore power, and confirm that E4 clears and frost buildup does not recur quickly.