Display shows E4 and the refrigerator exhibits heavy frost buildup on the evaporator or very poor cooling.

Safety: Unplug the refrigerator and wear cut-resistant gloves when working around metal panels and coils.

Steps:

• Access the evaporator: Remove freezer contents and the rear evaporator cover as described for other evaporator-related faults.
• Inspect frost pattern: A solid block of ice over the entire evaporator usually indicates a defrost failure.
• Locate defrost heater: The heater is typically a glass-encased or metal-sheathed element mounted at the bottom or woven through the evaporator coils.
• Check continuity: Disconnect the heater leads and test with a multimeter. A good heater will show continuity (low resistance). Infinite resistance indicates an open heater that must be replaced.
• Check defrost thermostat/bi-metal: This safety device is clipped to the evaporator tubing. When cold (below freezing), it should show continuity. If it remains open when cold, replace it.
• Inspect wiring: Look for burnt connectors or broken wires between the heater, thermostat, and harness.
• Manual defrost: While waiting for parts, you can defrost the evaporator by leaving the unit unplugged with doors open and towels on the floor. Do not chip ice with sharp tools.
• Replace failed parts: Install a Crosley-compatible defrost heater and/or defrost thermostat as needed, then reassemble and restore power.