Safety: Unplug the refrigerator before removing panels or working near the evaporator.

Access evaporator area: Empty the freezer, remove drawers and the rear interior panel to expose the evaporator coil.
Locate defrost sensor: The defrost thermistor is clipped to the evaporator tubing, often wrapped in foam or tape.
Check for heavy frost: If the coil is a solid block of ice, carefully defrost with a hair dryer on low, keeping the dryer away from plastic parts and wiring. Do not use sharp tools.
Inspect sensor and wiring: Look for cracked sensor housing, corroded connectors, or broken wires. Reseat the connector.
Test thermistor: Disconnect and measure resistance at around 32°F (0°C). Replace if open, shorted, or out of spec for LG thermistors.
Reassemble and test: After replacing the sensor, reassemble panels, restore power, and monitor for return of the error.
Control board check: If the new sensor does not clear the error, the main PCB may be faulty and should be evaluated by a technician.

Display shows “Er dS” and refrigerator may not cool properly or may run continuously.

Possible Causes