Samsung Refrigerator Error Code Fridge Off LED

The Fridge Off LED signals an R-DEF-Sensor error, indicating the refrigerator compartment defrost sensor has a faulty open circuit or short circuit condition. The main PCB monitors the voltage from this sensor on connector CN31 and triggers the error when the signal falls outside the expected 4.5V to 0.5V operating range. The refrigerator cannot safely manage its defrost cycle until the sensor or associated wiring is repaired.

Operating the refrigerator with an active defrost sensor fault is not recommended for extended periods. Without a functioning defrost sensor, the defrost cycle cannot terminate correctly, which can lead to excessive frost buildup on the evaporator coil and eventual loss of cooling. Food safety may be compromised if cooling performance degrades significantly.

A power reset may temporarily clear the displayed error, but the fault code will return as soon as the main PCB attempts to read the defrost sensor signal and detects the same out-of-range voltage. The underlying hardware problem, whether a failed sensor, damaged wiring, or connector fault, must be corrected before the error will clear permanently.

A knowledgeable DIYer can start by checking the wiring connectors at CN31 on the main PCB and the inline connector near the evaporator for loose or corroded pins. If connectors are secure, the defrost sensor thermistor can be tested for resistance and replaced if faulty. However, accessing the evaporator area requires removing interior panels, so comfort with appliance disassembly is necessary before attempting the repair.

If only the defrost sensor thermistor needs replacement, parts typically range from $15 to $50 depending on the model, with labor adding $80 to $150 if a technician performs the repair. If the wiring harness is damaged, costs can rise to $100 to $200 for parts and labor. A main PCB replacement, if required, is the most expensive outcome and can range from $150 to $400 or more including labor.