LG Refrigerator Er dH: The Defrost Heater Is Dead

Er dH means the defrost heater did not raise the evaporator area temperature during a scheduled defrost cycle. Every 8-12 hours, the board initiates a defrost cycle — it turns off the compressor, de-energizes the evaporator fan, and powers the defrost heater (a glass or calrod element behind the freezer rear panel). This heater melts frost that naturally accumulates on the evaporator coils during normal operation. When the heater fails, frost builds cycle after cycle until it encases the entire evaporator, blocks airflow, and kills cooling.

The Chain Reaction From Er dH

Er dH is the first domino. If not addressed:

Days 1-3: Frost thickens on evaporator coils. Cooling efficiency drops. Freezer temperature rises a few degrees.

Days 4-7: Frost blocks airflow through the evaporator fins. The evaporator fan runs but cannot push air through the ice mass. Both compartments warm noticeably.

Days 7-14: Ice encases the fan blade. Fan motor stalls — Er FF appears. Now both Er dH and Er FF are active. The fan motor may burn out from running at stall current.

Days 14+: Complete cooling loss. Compressor runs continuously with no temperature improvement. Food spoils.

This is why Er dH requires prompt attention — the defrost heater costs $30-50 to replace, but if ignored until the fan motor also fails, the repair cost doubles.

Diagnosing the Defrost System

The Defrost Heater (60% of Er dH)

The heater is a glass tube or calrod element mounted behind the freezer rear panel, running along the base of the evaporator coils.

Test:

1. Unplug the refrigerator. Remove the freezer rear panel (4-8 screws, may require removing shelves)
2. Disconnect the heater leads (2-wire connector at the edge of the evaporator frame)
3. Measure resistance: glass tube heaters typically read 15-30 ohms, calrod heaters read 20-50 ohms. Infinite = burned out
4. Also measure from either heater terminal to the metal evaporator frame: should be infinite. Any reading = glass tube cracked and grounded (ground fault)

A glass tube heater that shows correct resistance but has a visible hairline crack in the glass will eventually fail from moisture intrusion — replace prophylactically if cracked.

The Defrost Thermistor/Bi-Metal (25%)

The defrost system uses a temperature sensor (thermistor or bi-metal thermostat) that tells the board when to start and stop the heater. If this sensor reads incorrectly (reporting the evaporator is warm when it is actually frozen), the board never commands the heater on.

Test: the defrost bi-metal thermostat (a round disc mounted on the evaporator) should show continuity at freezer temperature and open circuit when warmed above approximately 45-50 degrees F. If it is stuck open at freezer temperature, the heater circuit is interrupted.

The Board's Defrost Relay (15%)

The main board has a dedicated relay for the defrost heater. If this relay fails open (contacts corroded), the board commands defrost but no power reaches the heater.

Test: during a forced defrost cycle (see below), measure voltage at the heater connector. If 120VAC is present and the heater has correct resistance but does not heat — unlikely scenario, suggests a connection issue. If 0V during defrost — board relay failure.

Forced Defrost Procedure

To force a defrost cycle on LG refrigerators:

1. Press and hold Refrigerator + Ice Plus simultaneously for 8 seconds
2. Display shows "OFF"
3. Press Refrigerator button repeatedly until "Fd" (Forced Defrost) appears
4. The unit runs a defrost cycle for approximately 20 minutes
5. You should hear the defrost heater click on and eventually water dripping as ice melts
6. If you hear clicking (relay closing) but no heating — heater is dead
7. If no clicking — board relay may be failed

Defrost Heater Replacement

1. Unplug refrigerator. Remove all freezer contents and shelves
2. Remove the freezer rear panel (screws around perimeter)
3. If heavy ice is present, perform a manual defrost first (hair dryer on low, or leave doors open for several hours with towels to catch water)
4. Disconnect the old heater leads
5. The heater mounts under the evaporator with clips or brackets — note orientation
6. Install the new heater (MEE62805001 or model-specific, $30-50) in the same position
7. Reconnect leads. Replace the rear panel. Restore shelves and food
8. Plug in and run a forced defrost to verify

Parts and Cost

Er dH and the Linear Compressor Warranty

The 10-year Linear Compressor warranty does not cover defrost system components (heater, bi-metal, defrost sensor). These fall under the standard 1-year warranty. However, if a failed defrost system causes the compressor to run continuously under ice-loaded conditions and the compressor subsequently fails, the compressor failure itself may be covered — document the Er dH history to support the claim.

Manual Defrost as a Temporary Measure

If you cannot get the heater replaced immediately, you can manually defrost to buy time:

1. Remove freezer contents to a cooler with ice
2. Unplug the refrigerator
3. Leave both doors wide open
4. Place towels on the floor to absorb meltwater
5. Wait 4-8 hours until all ice melts from the evaporator area
6. Plug back in. The fridge will cool normally for 2-4 days before frost re-accumulates enough to block airflow
7. Repeat as needed until the heater is replaced

This cycle of manual defrosting every 3-5 days is a reasonable short-term workaround but is not a permanent solution.

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LG refrigerator icing up inside? Er dH means the defrost heater failed — we carry replacements and complete the swap in under an hour. Book defrost repair.