LG Refrigerator Error Code Er dH — Defrost Heater Error
What this means
The Er dH error code indicates the LG refrigerator's defrost heater is not working correctly. The defrost heater periodically melts frost from the evaporator coils to maintain efficient cooling. When it fails, frost builds up on the evaporator, blocking airflow and causing the refrigerator and freezer to warm up over time.
Alternate codes: dH
Step-by-step fix
4 stepsCheck for frost on the evaporator
Remove the food from the freezer and unscrew the rear evaporator panel. If the evaporator coils are covered in thick frost or ice, the defrost heater has not been running. This confirms the Er dH diagnosis.
If you need to use the refrigerator immediately, use a hair dryer to carefully melt the frost from the coils as a temporary fix.
Test the defrost heater
Unplug the refrigerator. Locate the defrost heater — a glass tube or calrod element mounted along the evaporator coils. Disconnect its wires and test with a multimeter for continuity. A good heater will show continuity (typically 20–40 ohms). No continuity means it's burned out.
Test the defrost bi-metal thermostat
While you have access to the evaporator, also test the bi-metal thermostat (a small disc-shaped component on the evaporator). It should show continuity when cold (below approximately 40°F). If it's open at cold temperatures, it's stuck open and prevents the heater from receiving power.
The bi-metal thermostat is an inexpensive safety device — always test it when diagnosing defrost issues.
Replace the faulty component
Replace whichever component tested bad — the defrost heater, bi-metal thermostat, or both. Reassemble the evaporator panel, replace the food, and monitor the refrigerator for 24 hours.
When to call a professional
If both the heater and thermostat test fine, the defrost control on the main board may be faulty. The main board controls the defrost timer — a technician can test this circuit.
Related error codes
Information compiled from manufacturer service manuals, official troubleshooting documentation, and appliance repair industry resources. This guide is for informational purposes only — always consult a qualified technician for complex repairs.
Learn more about our sourcesParts you may need
Defrost Bi-Metal Thermostat
Part #6615JB2005H · $8–$18
If thermostat is stuck open when cold
Links may earn us a commission at no extra cost to you. We only recommend parts relevant to this repair.