LG Refrigerator Error Code F-defrost sensor open

This error means the control board has detected an open circuit in the freezer area defrost sensor. The sensor's resistance reading has fallen outside the valid range, which the board interprets as a temperature below -50°C. This typically points to a failed sensor thermistor, a broken wire, or a poor connection in the sensor circuit. The freezer's ability to properly manage defrost cycles may be compromised until the fault is resolved.

The refrigerator may continue to cool in the short term, but without a functioning defrost sensor, the defrost cycle cannot operate correctly. Over time this can lead to excessive frost buildup on the evaporator coils, reduced cooling efficiency, and potential damage to other components. It is best to address the fault promptly rather than continue running the unit with the error active.

A reset may temporarily clear the error code from the display, but the fault will return as long as the underlying problem with the sensor or wiring exists. The control board will detect the open circuit again during its next diagnostic cycle. Resetting the unit without completing a proper repair does not fix the sensor and should not be used as a substitute for diagnosing the root cause.

A knowledgeable DIYer can often diagnose this fault by testing the defrost sensor's resistance with a multimeter and inspecting the wiring harness and connectors for damage or corrosion. If the sensor itself has failed, replacing it is a straightforward repair that involves unplugging the refrigerator, accessing the sensor in the freezer compartment, and swapping in the correct replacement part. If the wiring or control board is involved, the repair becomes more complex and may benefit from professional service.

If only the defrost sensor needs replacement, parts typically cost between $15 and $50 depending on the specific model, and a DIY repair involves minimal additional expense. A professional repair, including parts and labor, generally ranges from $100 to $250. If the wiring harness or control board is also involved, costs can be higher.