LG Refrigerator Error Code 24

Error code 24 on an LG refrigerator indicates a fault in the freezer defrost heater circuit. This code triggers when the control board detects an abnormal condition during the automatic defrost cycle, specifically when defrost fails to complete within the 120-minute allotted window, or when the circuit reads outside expected parameters. The defrost heater is responsible for melting frost buildup on the evaporator coils at regular intervals, and any interruption in that process can lead to ice accumulation, restricted airflow, and eventual cooling failure throughout the refrigerator.

The fault can originate from several points in the defrost circuit. A slipped or corroded connector at the MAIN PCB CN70 port can interrupt signal continuity. A cut wire, an open thermal fuse, or a failed bimetal thermostat will each produce infinite resistance when tested. On the other end of the spectrum, a short-circuited heater element will show 0 ohms between the White and BLK wires at that connector. A defective defrost thermistor can also trigger this code, as the thermistor provides the temperature feedback the board uses to determine when the defrost cycle is complete.

Diagnosis begins at the MAIN PCB CN70 connector. Disconnecting this connector and checking continuity between the White and BLK wires reveals the nature of the fault: a reading of 0 ohms points to a shorted heater element, while an infinity reading indicates an open circuit somewhere along the path, which could be the heater itself, the thermal fuse, or the bimetal cutout. Visual inspection of wiring for cuts or pulled connectors should accompany electrical testing before any components are replaced.