Excessive frost or ice buildup on the back wall or around the evaporator.

Safety: Unplug the cooler before defrosting or accessing electrical components. Do not use sharp tools to remove ice.

Steps:

• Manual defrost: Remove all bottles, unplug the unit, and allow all ice to melt. Use towels to absorb water.
• Inspect door gasket and usage: Ensure the door seals tightly and limit frequent or prolonged openings, especially in humid conditions.
• Test defrost components: If frost returns within a week or two, remove the interior rear panel and test the defrost heater and thermistor as described in the E4 procedure.
• Replace faulty parts: Install a new defrost heater or thermistor if they test open or out of range.

Note: Some light frost is normal, but heavy, solid ice indicates a problem that should be corrected to maintain proper cooling.