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Error code reference

Amana Refrigerator Error Code THERMISTOR ALARM

Either freezer or refrigerator thermistor circuit is open; freezer or refrigerator indicator light shows and…

Amana codesAmana refrigerator codes

Either freezer or refrigerator thermistor circuit is open; freezer or refrigerator indicator light shows and temperature indicators 4 through 7 turn on in sequence.

First step from the service manual

Press Alarm Off pad to turn off alarm. Check thermistor resistance and wiring for open circuit.

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

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What THERMISTOR ALARM means on a Amana refrigerator

The THERMISTOR ALARM on an Amana refrigerator indicates that either the freezer thermistor circuit or the refrigerator compartment thermistor circuit has developed an open condition. A thermistor is a temperature-sensitive resistor that the control board uses to monitor compartment temperatures in real time. When the circuit opens, the control board loses its temperature signal entirely, triggering the alarm. The freezer or refrigerator indicator light will illuminate on the display, and temperature indicators 4 through 7 will cycle on in sequence to alert the user.

An open thermistor circuit means the electrical path between the thermistor and the control board has been broken. This can result from a failed thermistor whose internal resistance has gone out of range, a disconnected or corroded wiring harness connector, or physical damage to the wiring itself. Because the control board relies on thermistor feedback to regulate compressor and fan operation, a loss of this signal can affect temperature management in the affected compartment.

Diagnosing the fault begins with pressing the Alarm Off pad to silence the audible alarm. From there, the thermistor resistance should be measured directly at the component and compared against the expected value for the operating temperature. The wiring harness between the thermistor and the control board should also be inspected for breaks, pinched sections, or loose connector pins. Identifying whether the fault is in the thermistor itself or in the wiring determines the correct repair path.

Source: manufacturer service documentation.

Common causes of THERMISTOR ALARM

  1. 01

    Failed thermistor

    Part replacement

    The thermistor itself has failed internally, causing its resistance to fall outside the acceptable range or the circuit to go completely open. Resistance can be measured at the thermistor terminals to confirm whether the component has failed.

  2. 02

    Disconnected wiring harness connector

    Wiring / connection

    The connector linking the thermistor to the control board wiring harness may have come loose due to vibration or handling during a previous repair. Visually inspecting and firmly reseating the connector can resolve this without replacing any parts.

  3. 03

    Damaged or broken thermistor wiring

    Part replacement

    The wiring between the thermistor and the control board may be pinched, broken, or chafed, creating an open circuit. Carefully tracing the harness through the refrigerator compartment can reveal the damaged section.

  4. 04

    Corroded or oxidized connector pins

    Wiring / connection

    Moisture exposure in the refrigerator or freezer compartment can cause connector pins to corrode, increasing resistance to the point of an open circuit. Inspecting the connector terminals for discoloration or buildup and cleaning them can restore proper continuity.

  5. 05

    Faulty control board

    Part replacement

    In less common cases, the control board's thermistor input circuit may have failed, causing it to read an open circuit even when the thermistor and wiring are intact. This is typically confirmed only after the thermistor and wiring have been tested and found good.

See the test procedure for each cause

Frequently asked questions about THERMISTOR ALARM

What does THERMISTOR ALARM mean on a Amana refrigerator?
The THERMISTOR ALARM means the control board has detected an open circuit in either the freezer or refrigerator compartment thermistor. The thermistor is a temperature sensor the refrigerator uses to monitor and regulate internal temperatures. When this circuit breaks, the alarm sounds and temperature indicators 4 through 7 illuminate in sequence on the display. The fault must be diagnosed by checking the thermistor resistance and the associated wiring.
Can I reset the THERMISTOR ALARM myself?
You can silence the alarm by pressing the Alarm Off pad on the control panel. However, this only mutes the alert and does not fix the underlying open circuit in the thermistor or its wiring. The alarm will return if the fault is not corrected. A proper repair requires testing the thermistor resistance and inspecting the wiring harness.
Is it safe to keep using my refrigerator while the THERMISTOR ALARM is active?
Operating the refrigerator with an active thermistor alarm carries some risk, because the control board may not be able to accurately regulate temperatures in the affected compartment. Food safety could be compromised if the compartment temperature rises without the board detecting it. It is best to check the compartment temperature with a separate thermometer and address the fault promptly.
How much does it cost to fix a THERMISTOR ALARM on an Amana refrigerator?
Repair costs vary depending on whether the thermistor itself, the wiring, or another component is at fault. A replacement thermistor typically costs in the range of $15 to $50 for the part alone. If professional labor is required, total repair costs including diagnosis and labor can range from $100 to $250 or more depending on your location and service provider.
Will the THERMISTOR ALARM clear on its own once the problem is fixed?
Once the open circuit in the thermistor or wiring has been repaired and the circuit continuity is restored, the control board should recognize a valid temperature signal and the alarm condition should clear. Pressing the Alarm Off pad can silence the alert during diagnosis. If the alarm persists after the circuit is repaired, the control board input may need to be evaluated.

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