LG Refrigerator Error Code R-defroster sensor open

This fault code means the control board has detected an open circuit in the refrigerator compartment defrost sensor, interpreting the reading as below -50°C. The defroster sensor is a thermistor that monitors evaporator temperature during defrost cycles. When it goes open circuit, the board cannot properly manage the defrost heater. The fault is typically caused by a failed sensor, broken wiring, or a corroded connector.

The refrigerator may continue cooling in the short term, but without a functioning defroster sensor the defrost cycle cannot operate correctly. Over time, ice will accumulate on the evaporator, which can restrict airflow and lead to rising temperatures inside the refrigerator compartment. It is best to have the fault diagnosed and repaired promptly to avoid food spoilage or further component damage.

A power reset may temporarily clear the displayed fault code, but the error will return if the underlying open circuit condition still exists. The self-test function should be used to confirm whether the fault is still active after any reset. Permanently clearing the code requires repairing or replacing the defective sensor or wiring causing the open circuit.

A knowledgeable DIYer can address this fault by first running the refrigerator's self-test function to confirm the code is active. From there, inspect the wiring harness and connectors from the sensor to the control board for any visible damage or loose connections. If those check out, replacing the R-area defroster sensor is the confirmed next step. Working around the evaporator requires removing the interior back panel of the refrigerator compartment, which is manageable but does require some disassembly.

If only the defroster sensor needs to be replaced, parts typically cost in the range of $15 to $50 depending on the specific LG model. If a technician performs the repair, total costs including labor generally range from $100 to $200. If the control board or additional wiring repairs are needed, costs can be higher.