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Error code reference

GE Refrigerator Error Code F8

Ambient Temperature Thermistor Invalid

GE codesGE refrigerator codes

Ambient Temperature Thermistor Invalid - thermistor is shorted, open, or outside normal operating range.

First step from the service manual

Check thermistor resistance; replace if open or shorted.

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

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What F8 means on a GE refrigerator

The F8 error code on a GE refrigerator indicates an Ambient Temperature Thermistor Invalid fault. The ambient thermistor is a negative temperature coefficient (NTC) sensor that monitors the air temperature surrounding the refrigerator's control board or interior environment. The control board continuously reads the thermistor's resistance value and converts it to a temperature reading. When the resistance falls outside the expected operating range, either by dropping too low (shorted condition) or climbing too high or to infinity (open circuit condition), the board flags the F8 code because it can no longer trust the sensor input.

A shorted thermistor typically produces a resistance reading near zero ohms, while an open thermistor produces no continuity at all. Either condition causes the control board to lose its reference point for ambient temperature compensation, which can affect defrost timing, compressor cycling logic, and other temperature-dependent functions. The thermistor itself, the wiring harness connecting it to the board, and the connector terminals are all potential failure points.

Common root causes include physical damage to the thermistor probe, corrosion at the connector pins, wiring that has been pinched or chafed through, and in some cases outright thermistor component failure due to age or moisture exposure. Because ambient temperature data feeds into the refrigerator's broader control logic, leaving the F8 fault unresolved can result in inaccurate temperature regulation and increased energy consumption.

Source: manufacturer service documentation.

Common causes of F8

  1. 01

    Failed Ambient Thermistor

    Part replacement

    The thermistor itself has failed internally, resulting in either a short (near-zero resistance) or an open circuit (no continuity). Checking resistance across the thermistor terminals will confirm this; a good thermistor shows a predictable resistance that changes with temperature, while a failed one reads zero or infinite ohms.

  2. 02

    Damaged Wiring Harness

    Part replacement

    The wiring between the thermistor and the control board may be pinched, chafed, or broken, creating an open or short circuit in the circuit before the sensor itself. Inspect the full length of the harness for visible damage, especially near routing clips and sharp edges.

  3. 03

    Corroded or Loose Connector Pins

    Wiring / connection

    Moisture or age can cause corrosion at the thermistor connector, increasing resistance or breaking the circuit intermittently. Inspect the connector for green or white oxidation on the terminals and ensure the connector is fully seated.

  4. 04

    Moisture Intrusion at the Sensor

    Wiring / connection

    Water or condensation around the thermistor probe can cause erratic resistance readings or accelerate sensor failure. Check the mounting location of the thermistor for signs of moisture accumulation or ice buildup.

  5. 05

    Faulty Control Board

    Part replacement

    If the thermistor and wiring both test within normal parameters, the control board's thermistor input circuit may have failed. This is the least common cause and should be diagnosed only after ruling out the sensor and wiring.

See the test procedure for each cause

Frequently asked questions about F8

What does F8 mean on a GE refrigerator?
The F8 code on a GE refrigerator indicates an Ambient Temperature Thermistor Invalid fault. It means the control board is detecting that the ambient thermistor is either shorted, open, or reading outside its normal operating range. The thermistor is a resistance-based temperature sensor, and when its output is invalid, the board triggers this code to alert the user to a sensor circuit problem.
Can I fix the F8 error code on my GE refrigerator myself?
A knowledgeable DIYer can address the F8 code by first inspecting the thermistor wiring and connectors for visible damage or corrosion, then testing the thermistor's resistance with a multimeter. If the sensor reads open or shorted, replacing the ambient thermistor is a straightforward repair. If wiring damage is found, repairing or replacing the affected harness section may also resolve the fault.
Is it safe to continue using my GE refrigerator when it shows the F8 code?
The F8 code itself does not indicate an immediate safety hazard, but the refrigerator may not regulate temperature as accurately without a valid ambient thermistor input. Over time, this can affect food preservation and lead to additional component stress. It is best to diagnose and resolve the fault promptly rather than ignoring it.
How much does it cost to repair a GE refrigerator showing an F8 error?
If only the ambient thermistor needs replacement, parts typically cost in the range of $15 to $50 depending on the specific model, and the repair is relatively simple. If a technician is needed, labor charges can bring the total to roughly $100 to $200. Wiring harness repairs or a control board replacement would increase costs further, potentially ranging from $150 to $400 or more.
Will resetting my GE refrigerator clear the F8 error code?
A power reset may temporarily clear the F8 code, but if the thermistor or its wiring circuit is genuinely faulty, the code will return once the control board re-evaluates the sensor input. A reset is useful for ruling out a transient glitch, but a persistent F8 code requires physical diagnosis and likely component replacement to resolve permanently.

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