Samsung Refrigerator Error Code DEFROST SENSOR OF R ROOM

This error means the main control board has detected a problem with the defrost sensor in the refrigerator compartment. The sensor is reporting a temperature outside the valid range (above 122°F or below -58°F), or the circuit has an open or short circuit. The board cannot properly control defrost cycles without a valid sensor reading.

The refrigerator will likely continue cooling in the short term, but it is not safe to ignore this error indefinitely. Without a functioning defrost sensor, the control board cannot run defrost cycles correctly, which leads to ice accumulation on the evaporator coil and progressive loss of cooling. Food safety will be at risk once airflow is significantly restricted, so the repair should be completed promptly.

Use a multimeter set to DC voltage and probe the sensor connector pins on the main PCB with the refrigerator powered on. A reading between 1.0V and 4.5V indicates the sensor circuit is within normal range. A reading outside this window, or no voltage at all, points to a failed sensor, open wiring, or a shorted harness. You can also test sensor resistance directly after disconnecting it; compare the resistance value against the temperature-resistance chart in the Samsung service manual for your specific model.

Start by measuring the voltage at the main PCB sensor connector; it should read between 1.0V and 4.5V. If the voltage is out of range, inspect the wiring harness and connectors between the sensor and the PCB for breaks, corrosion, or loose connections. If the harness checks out, replace the refrigerator compartment defrost sensor. If replacing the sensor does not resolve the code, the main PCB may need to be tested or replaced.

If the defrost sensor is the only failed component, the part typically costs between $10 and $40, and replacing it is a DIY-friendly repair requiring basic tools and a multimeter. If the main PCB is also faulty, board replacements range from $100 to $300 for the part alone. A professional technician visit adds $80 to $150 in labor on top of parts.