LG Refrigerator Sensor Replacement

A modern LG refrigerator does not guess at temperature — it measures it with NTC thermistors, small resistance sensors whose resistance falls as they warm. The main control reads each one to decide when to run the compressor, open the damper, and start a defrost. When a thermistor drifts or fails, the control acts on bad data, so the fridge over-cools, under-cools, or never defrosts even though the hardware is fine.

Where the Thermistors Live#

• A fresh-food thermistor reports the refrigerator compartment temperature
• A freezer thermistor reports the freezer temperature
• A defrost thermistor on the evaporator tells the control when the coil is cold enough to end a defrost

A fault in any one produces its own pattern, so identifying which compartment is misbehaving points you at the sensor to test.

Symptoms of a Failing Thermistor#

• The refrigerator or freezer runs noticeably warmer or colder than the setpoint
• The compressor runs constantly, or barely runs, because it is fed a wrong reading
• Frost builds on the evaporator or in the compartment as defrost timing goes wrong
• Displayed temperature does not match an independent thermometer inside

Testing the Thermistor by Resistance#

The clean way to confirm a thermistor is to measure its resistance and compare it to temperature. Unplug the refrigerator, unclip the sensor, and set a multimeter to resistance. An NTC thermistor reads higher resistance when cold and lower when warm — so a sensor sitting at freezer temperature near 0°F reads high, one at a chilled 32°F reads lower, and one at room temperature near 72°F reads lower still. Compare your reading against the LG resistance chart for that temperature; a value far off the chart, or an open or shorted reading, confirms the thermistor has failed.

Step-by-Step Replacement#

1. Unplug the refrigerator.
2. Locate the failed thermistor — clipped to the compartment wall for air sensors, or on the evaporator behind the rear panel for the defrost sensor.
3. For a defrost sensor, remove the interior rear panel to expose the coil; the sensor clips to the tubing.
4. Photograph and release the sensor's wire connector.
5. Unclip the old thermistor and fit the new EBG61285804, routing the wire the same way.
6. Refit any panel, restore power, and confirm the compartment reaches and holds the setpoint against a separate thermometer.

Tools You Will Need#

• A nut driver and screwdriver for the rear evaporator panel
• A multimeter to measure resistance against the LG chart
• A separate thermometer to confirm the fix

Common Mistakes to Avoid#

• Replacing the control board before testing the cheap thermistor, which is the more common cause of temperature drift.
• Guessing by feel instead of measuring resistance against the chart.
• Disturbing the defrost sensor's contact with the evaporator, which throws off defrost timing.

Repair or Replace the Refrigerator#

A thermistor is one of the cheapest parts in the refrigerator, so replacing it is always worthwhile. Only weigh a new unit if the sealed system or compressor has also failed.

What It Costs#

LG does not publish one price — the sensor is inexpensive and most of any professional charge is the trip and labor. Because the part is cheap and testable, this is a strong DIY value. Match EBG61285804 to your model before ordering.

How Long It Lasts#

A refrigerator thermistor commonly lasts the life of the appliance. When one fails early, moisture intrusion at the connector is the usual cause, so making sure the sensor clip and connector stay dry and seated helps it last.