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Error code reference

LG Refrigerator Error Code R-DEFROSTING ERROR

R compartment defrosting heater error

LG codesLG refrigerator codes

R compartment defrosting heater error: electric wire cut, short-circuit, contact failure, sensor housing missing, or defective temperature fuse; defrost not finished after continuous heating for more than 70 min.

First step from the service manual

After separating Main PCB CN70 wire from the PCB, check resistance between white ↔ orange color to see if it is between 300 and 400Ω.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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  • Wiring diagram references and connector pinouts from the OEM service manual
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What R-DEFROSTING ERROR means on a LG refrigerator

The R-DEFROSTING ERROR on an LG refrigerator indicates a fault in the refrigerator (R) compartment defrost circuit. This error is triggered when the defrost cycle fails to complete within 70 continuous minutes of heater operation. The defrost system relies on a heating element, a temperature fuse, wiring connections, and a thermistor or sensor to regulate and terminate the defrost cycle safely. When any of these components fail, the system cannot properly melt frost buildup on the evaporator coil, leading to reduced cooling performance and ultimately this fault code.

The most direct diagnostic starting point involves the Main PCB connector CN70. By disconnecting the CN70 wire harness from the PCB and measuring resistance between the white and orange wires, a technician can immediately assess heater circuit continuity. A healthy defrost heater circuit should read between 300 and 400 ohms. A reading of infinite resistance (open circuit) points to a wire break or a blown thermal fuse, while a reading near zero ohms suggests a short circuit in the heater element or wiring. Readings outside the 300 to 400 ohm window but not clearly open or shorted may indicate contact failure at a connector or terminal.

Beyond wiring and heater integrity, a missing or improperly seated sensor housing can prevent accurate temperature readings, causing the control board to run the defrost heater indefinitely. A defective thermal fuse, which is a one-time safety cutoff device, will open the circuit permanently once it trips and must be replaced before the defrost system will function again. All of these failure points feed into the same error code, so a systematic component-by-component check is required to isolate the root cause.

Source: manufacturer service documentation.

Common causes of R-DEFROSTING ERROR

  1. 01

    Blown or open thermal fuse

    Part replacement

    The thermal fuse is a one-time safety device that permanently opens the circuit if it overheats. A blown fuse will show infinite resistance between the white and orange wires at CN70, well outside the 300 to 400 ohm normal range. The fuse must be replaced to restore the circuit.

  2. 02

    Defrost heater failure (open or short circuit)

    Part replacement

    The defrost heater element itself can fail either by breaking internally (open circuit, infinite resistance) or by shorting (near-zero resistance). Both conditions are identifiable during the CN70 resistance check between the white and orange wires.

  3. 03

    Wiring break or contact failure

    Wiring / connection

    A cut wire or loose connector in the defrost heater circuit will interrupt current flow and prevent defrosting from completing. Inspect the wiring harness leading to the heater and fuse for visible damage, corrosion, or loose terminals at connectors.

  4. 04

    Missing or improperly seated sensor housing

    Part replacement

    If the temperature sensor housing is absent or not correctly positioned on the evaporator, the control board cannot accurately detect when defrost is complete. This can cause the system to run the heater indefinitely until the 70-minute timeout triggers the error.

  5. 05

    Defective defrost temperature sensor

    Part replacement

    A faulty sensor can send incorrect temperature readings to the Main PCB, preventing proper termination of the defrost cycle even when the heater is functioning. This would cause repeated 70-minute timeout faults without a clear heater wiring issue.

See the test procedure for each cause

Frequently asked questions about R-DEFROSTING ERROR

What does R-DEFROSTING ERROR mean on a LG refrigerator?
This error means the defrost system in the main refrigerator compartment has failed or could not complete a defrost cycle within 70 continuous minutes of heater operation. It points to a problem in the defrost heater circuit, which could involve the heating element, thermal fuse, wiring, sensor housing, or sensor itself. The refrigerator will likely experience reduced cooling efficiency as frost accumulates on the evaporator coil until the fault is resolved.
Can I fix the R-DEFROSTING ERROR myself?
A knowledgeable DIYer can perform initial diagnostics by disconnecting connector CN70 from the Main PCB and measuring resistance between the white and orange wires. A correct reading falls between 300 and 400 ohms. If the reading is out of range, the fault is likely in the heater, thermal fuse, or wiring, all of which are serviceable components. However, working around electrical components in a refrigerator requires care, and replacement of a Main PCB or internal wiring harness may be better handled by a qualified technician.
Is it safe to use my LG refrigerator while this error is displayed?
A non-functional defrost system will cause frost to build up on the evaporator coil over time, gradually reducing the refrigerator's ability to maintain safe food storage temperatures. While the appliance is not an immediate electrical hazard in most cases, continued use without repair risks food spoilage and can eventually cause the compressor to overwork. It is best to address the error promptly rather than rely on the appliance for critical food storage.
Will resetting my LG refrigerator clear this error code?
A power reset may temporarily clear the error code from the display, but the underlying fault in the defrost circuit will remain. The code will return once the refrigerator attempts another defrost cycle and encounters the same problem. A reset is useful for confirming whether the fault is intermittent, but it does not substitute for diagnosing and repairing the root cause.
How much does it cost to repair the R-DEFROSTING ERROR on an LG refrigerator?
Repair costs depend on which component has failed. A thermal fuse or defrost heater element are relatively inexpensive parts, typically in the range of $10 to $50 each, though labor costs for a professional technician can bring the total to $100 to $250 or more. A defective sensor or damaged wiring harness falls in a similar range. Main PCB replacement is significantly more expensive, often $150 to $400 or higher for parts alone, and is only necessary if the board itself is confirmed faulty.

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