Display shows E4; freezer or fridge may be warm and heavy frost forms on evaporator or rear wall.

Safety first: Unplug the refrigerator. The defrost heater operates at mains voltage and can cause electric shock.

Access the defrost components:

• Remove freezer drawers and shelves.
• Unscrew and remove the rear interior panel to expose the evaporator and heater assembly.

Visual inspection:

• Look for a metal or glass-tube heater element attached to the bottom or around the evaporator.
• Check for burn marks, broken heater casing, or melted connectors.
• Locate any thermal fuse or defrost thermostat clipped to the evaporator tubing and inspect for damage.

Basic electrical checks (for competent DIYers):

• With the appliance unplugged, disconnect the heater terminals and measure resistance. An infinite reading indicates a failed heater.
• Check continuity through the thermal fuse/defrost thermostat; an open device (at room temperature) may be faulty.

Replace faulty parts:

• If the heater is open, replace it with a Finlux-compatible defrost heater assembly.
• If the thermal fuse or thermostat is open, replace with the exact temperature-rated Finlux part and clip it back to the same pipe location.
• Ensure all connectors are tight and not heat-damaged.

Reassemble and test: Refit the rear panel, restore power, and allow 24 hours. The E4 code should clear and frost should no longer accumulate excessively.

Warning: If you are not experienced with mains-voltage testing, do not attempt live tests. A technician should check the PCB defrost relay and supply if the heater circuit tests good but E4 persists.