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Error code reference

LG Refrigerator Error Code R-defroster sensor short

Refrigerator area defroster sensor short circuit fault

LG codesLG refrigerator codes

Refrigerator area defroster sensor short circuit fault — sensor reading suspected to be over +50°C.

First step from the service manual

Run self-test function; replace R-area defroster sensor if confirmed.

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

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What R-defroster sensor short means on a LG refrigerator

The R-defroster sensor short fault indicates that the refrigerator compartment defrost temperature sensor has reported a short circuit condition. In this context, the control board interprets a short circuit as a sensor reading above +50°C, which is physically implausible during normal operation and signals an electrical fault rather than an actual temperature event. The defrost sensor in the refrigerator section monitors temperatures during the defrost cycle to prevent the heater from running too long and causing damage to the liner or food compartment.

A short circuit in the sensor circuit typically means the sensor's internal resistance has dropped to near zero, or the wiring harness has a fault causing two conductors to contact each other. NTC thermistor-type sensors like those used in LG refrigerator defrost circuits normally present a specific resistance value that decreases predictably with rising temperature. When the resistance collapses due to a shorted sensor body or wiring fault, the control board sees a signal consistent with an extreme high-temperature reading and logs this fault code.

Diagnosing this fault starts with running the refrigerator's built-in self-test function to confirm the fault is active and not a stored ghost code. If the fault is confirmed, the technician should inspect the sensor wiring harness for pinched wires, heat damage near the defrost heater, or corroded connector terminals before condemning the sensor itself. If wiring checks out, the R-area defroster sensor should be replaced.

Source: manufacturer service documentation.

Common causes of R-defroster sensor short

  1. 01

    Failed defrost sensor (internal short)

    Part replacement

    The NTC thermistor inside the sensor body can fail internally, causing its resistance to collapse and simulate a short circuit. This is the most common cause and is confirmed when resistance measured across the sensor terminals reads near zero ohms.

  2. 02

    Damaged wiring harness near defrost heater

    Part replacement

    The defrost heater generates significant heat and can melt or degrade the insulation on nearby wiring over time, causing two conductors to contact each other and create a short. Inspect the harness routing near the heater for any visible melting, scorching, or chafing.

  3. 03

    Corroded or shorted connector terminals

    Wiring / connection

    Moisture in the freezer or refrigerator section can infiltrate the sensor's electrical connector, causing corrosion that bridges the terminals and creates a low-resistance short. Inspect the connector for discoloration, moisture, or visible corrosion buildup.

  4. 04

    Pinched wiring during a previous repair

    Wiring / connection

    If the refrigerator has been serviced recently, sensor wiring may have been pinched between panels or brackets during reassembly, causing an intermittent or permanent short circuit. Trace the full length of the harness and check for any compression points.

  5. 05

    Faulty main control board

    Part replacement

    In rare cases, the control board itself may misread a healthy sensor circuit due to a failure on the input sensing circuitry. This should only be suspected after the sensor and wiring have been tested and confirmed good.

See the test procedure for each cause

Frequently asked questions about R-defroster sensor short

What does R-defroster sensor short mean on a LG refrigerator?
This error code means the refrigerator compartment defrost sensor has been detected as having a short circuit fault. The control board sees a sensor reading that corresponds to a temperature above +50°C, which indicates an electrical problem with the sensor or its wiring rather than an actual temperature condition. The defrost system may be disabled or behave abnormally while this fault is active.
Can I fix the R-defroster sensor short error myself?
A knowledgeable DIYer can attempt to diagnose this fault by running the refrigerator's self-test mode and then visually inspecting the sensor wiring harness and connector for damage or corrosion. If the sensor itself has failed internally, replacing the R-area defroster sensor is a straightforward repair that involves unplugging the old sensor and plugging in the new one. However, if the wiring harness is damaged or the control board is suspected, professional repair is recommended.
Is it safe to keep using my LG refrigerator when this error appears?
The refrigerator may continue to cool in the short term, but with the defrost sensor faulty, the defrost cycle cannot be properly controlled. Over time this can lead to excessive frost buildup on the evaporator coil, which reduces cooling efficiency and can eventually cause the refrigerator to stop cooling altogether. It is best to address the fault promptly to avoid food spoilage.
How much does it cost to fix a R-defroster sensor short on an LG refrigerator?
If only the defrost sensor needs replacement, parts typically cost in the range of $15 to $50 depending on the specific model, and a professional technician's labor for this repair generally adds $80 to $150. If the wiring harness or control board is also involved, total repair costs can rise to the $150 to $400 range. Getting a diagnosis first helps confirm exactly which components need to be replaced.
Will resetting my LG refrigerator clear the R-defroster sensor short error?
A power reset may temporarily clear the fault code from the display, but the error will return if the underlying short circuit in the sensor or wiring is still present. The self-test function should be used to confirm whether the fault is still active after a reset. Clearing the code without repairing the root cause does not resolve the defrost system problem.

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