Refrigerator displays F5; unit may not defrost properly, leading to ice buildup and warm temperatures.

Safety: Disconnect power before accessing the evaporator or electrical components. Risk of electric shock and sharp metal edges.

F5 points to a problem in the defrost system.

• Check for ice buildup: Remove freezer drawers and rear panel. If the evaporator is heavily iced, the defrost system is likely not working.
• Inspect defrost heater: The heater is usually attached to or beneath the evaporator coil. Look for burn marks, breaks, or disconnected wires.
• Test heater continuity: With the heater disconnected and the unit unplugged, use a multimeter to check for continuity. An open circuit indicates a failed heater that must be replaced.
• Check defrost thermostat/thermal fuse: Locate the defrost thermostat clipped to the evaporator tubing. At freezing temperatures, it should show continuity. If open when cold, replace it.
• Examine wiring: Follow the heater and thermostat wires back to the harness. Repair any burnt or broken wires using proper connectors and heat-shrink tubing.
• Control board check: If heater and thermostat test good, the defrost relay or control board may not be energizing the heater. This typically requires a technician to diagnose and replace the main PCB.