Defrost Heater Error

What it means

This code appears on LG refrigerators with a digital display and means the defrost cycle did not complete properly, usually because the defrost heater, its thermal fuse or its wiring is not working. Over time ice builds up on the evaporator behind the freezer's inner cover and blocks the airflow. The refrigerator keeps running but cooling weakens gradually; the same code can mean something else on other brands.

Models covered: LG refrigerators with a digital display (e.g. side-by-side, French door and top-freezer models); the code shows as Er plus two letters.

Related codes: ER DSER FFER FS

Symptoms5

• Er dH shows on the refrigerator display.
• Heavy frost on the back wall inside the freezer.
• Cooling weakens gradually, especially in the fresh food section.
• Scraping from the freezer fan because of ice.
• Water collecting under the drawers at times.

Possible causes5

• Failed defrost heater or an open heater element.
• Open thermal fuse in the defrost circuit.
• Loose or corroded heater connector from moisture.
• A defrost sensor fault that stops the cycle starting or ending correctly.
• A fault in the heater relay on the main board.

How to diagnose5

1. Unplug the refrigerator for a few minutes and plug it back in; if the code returns, the fault is real.
2. Look inside the freezer: heavy frost on the back wall confirms defrost is not working.
3. Move sensitive food to another cold place if cooling starts to weaken, and keep the doors closed.
4. A technician unplugs the refrigerator before removing the inner cover, then measures the heater and thermal fuse against the manufacturer specification.
5. The technician checks the defrost sensor and connectors, then the main board output to the heater if those parts test good.

How to fix6

1. Repair a corroded heater connector or wiring.
2. Replace an open thermal fuse once the reason it opened is known.
3. Replace the defrost heater if it is proven faulty.
4. Replace the defrost sensor if its reading is out of specification.
5. Replace the main board only if it is proven not to power the heater.
6. The technician melts all the built-up ice, then the refrigerator is run to confirm cooling returns without the code.

The usual repair is a heater or thermal fuse at moderate cost; it is cheaper for a corroded connector and higher only if the main board is at fault.

Prices are rough estimates including the part and the technician’s fee, and vary with brand, model and part source.
Prices last updated: September 2026

Frequently asked questions