Ice maker stops mid-cycle and displays E04, ice plate heavily frosted or iced over

Safety first: Disconnect power before accessing internal components. Avoid using sharp tools to remove ice.

Steps to address:

• Manual defrost: Remove ice bin and any loose ice. Leave the door open and allow the unit to thaw for several hours, or use a hair dryer on low setting at a safe distance to gently melt ice on the evaporator plate. Do not overheat plastic parts.
• Access evaporator area: Remove the inner cover to expose the evaporator plate, harvest heater, and defrost thermostat/thermistor.
• Check heater continuity: With the unit unplugged, disconnect the heater leads and test with a multimeter. A good heater shows finite resistance; an open circuit means it must be replaced.
• Test defrost thermostat: If fitted, test the thermostat for continuity when cold (placed in ice water). It should close at low temperature. Replace if it remains open.
• Inspect wiring: Look for broken or brittle wires around the heater and thermostat. Repair or replace damaged harness sections.

Note: If heater and thermostat test good, the main control board may not be energizing the heater. In that case, a board replacement is usually required and is best done by a professional.