LG Refrigerator Error Code FF-DEF-HEATER Error

This error means the defrost system in the fresh food compartment has detected a fault. Specifically, the defrost heater ran continuously for more than 80 minutes without the cycle completing successfully. The refrigerator displays this code to alert you that frost may be building up on the evaporator coils, which will eventually reduce cooling performance in the fresh food section.

Start by disconnecting main PCB connectors CN70 and CN71, then measure resistance between the CN70 White wire and the CN71 Orange wire. The reading should be 63 ohms plus or minus 7% for 230-volt models. If the resistance is out of range, the heater element needs to be replaced. If the heater tests good, check the thermal fuse for continuity and the defrost thermostat for proper operation before considering the main PCB.

Repair costs depend on which component has failed. A replacement defrost heater element typically ranges from 30 to 80 dollars for the part, while a thermal fuse or defrost thermostat usually costs between 10 and 40 dollars. If a main PCB replacement is required, parts alone can range from 100 to 300 dollars or more. Adding professional labor, total repair costs commonly fall between 150 and 450 dollars depending on the diagnosis.

A power reset may temporarily clear the error code, but it will return if the underlying fault in the defrost circuit is not repaired. The heater element, thermal fuse, thermostat, and associated wiring all need to be tested and confirmed functional before the error will stay cleared. Resetting without repair may also allow frost to continue accumulating on the evaporator coils.

The error itself is a protective feature designed to prevent the defrost heater from running indefinitely, which could cause overheating damage. However, if frost is allowed to build up heavily on the evaporator coils over time, cooling efficiency will decline and food spoilage can result. Addressing the fault promptly is recommended to keep the fresh food compartment at safe temperatures.