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Error code reference

Norcold Refrigerator Error Code Flashing Temp Setting

Thermistor failure; controls have shifted to Backup Operating System (BOS) mode.

Norcold codesNorcold refrigerator codes

Thermistor failure; controls have shifted to Backup Operating System (BOS) mode.

First step from the service manual

Check thermistor wire assembly and connector for dirty/broken connections at P1 connector terminals 8 and 13.

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

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What Flashing Temp Setting means on a Norcold refrigerator

When the temperature setting display flashes on a Norcold refrigerator, it indicates a thermistor failure has been detected by the control board. The thermistor is a temperature-sensing resistor that continuously reports compartment temperature to the control system. When the control board loses a valid signal from the thermistor, it recognizes the fault and automatically shifts operation to Backup Operating System (BOS) mode. In BOS mode, the unit continues to run but without closed-loop temperature feedback, meaning it cannot accurately regulate or maintain precise compartment temperatures.

The thermistor circuit connects to the main control board through the P1 connector, specifically at terminals 8 and 13. These terminals carry the low-voltage signal from the thermistor wire assembly back to the board. Failures most often originate at the connector interface rather than the thermistor itself. Corrosion, moisture intrusion, or physical damage at the P1 connector can increase circuit resistance or break continuity entirely, producing the same fault condition as a failed thermistor.

If the connector and wiring check out clean and intact, the thermistor itself may have drifted out of its acceptable resistance range or failed open or short. A thermistor that reads incorrectly will cause the control board to reject the signal and revert to BOS mode. Diagnosing this fault requires inspecting the P1 connector at terminals 8 and 13 first, then testing the thermistor wire assembly for continuity and proper resistance before condemning any individual component.

Source: manufacturer service documentation.

Common causes of Flashing Temp Setting

  1. 01

    Dirty or corroded P1 connector at terminals 8 and 13

    Wiring / connection

    Corrosion, moisture, or debris at the P1 connector terminals 8 and 13 can interrupt the thermistor signal to the control board. Inspect the connector for discoloration, oxidation, or visible moisture and clean or reseat the connection.

  2. 02

    Broken or damaged thermistor wire assembly

    Part replacement

    Physical damage to the wiring between the thermistor and the P1 connector, such as a pinched, frayed, or broken wire, can cause an open circuit in the signal path. Check the full length of the wire harness for visible damage.

  3. 03

    Failed thermistor

    Part replacement

    The thermistor itself may have failed open, shorted, or drifted outside its acceptable resistance range, causing the control board to reject its signal. If the connector and wiring are both confirmed good, the thermistor should be tested for proper resistance and replaced if it reads incorrectly.

  4. 04

    Loose connector seating at P1

    Wiring / connection

    Vibration during travel in an RV application can cause the P1 connector to work loose from the control board. A connector that is not fully seated will produce an intermittent or complete loss of thermistor signal.

  5. 05

    Control board failure

    Part replacement

    If the thermistor, wiring, and P1 connector all test correctly, the control board itself may have failed and is no longer processing the thermistor input properly. This is the least common cause and should only be considered after all other components are confirmed good.

See the test procedure for each cause

Frequently asked questions about Flashing Temp Setting

What does Flashing Temp Setting mean on a Norcold refrigerator?
A flashing temperature setting display on a Norcold refrigerator indicates that the control board has detected a thermistor failure and has shifted the unit into Backup Operating System (BOS) mode. The thermistor is the sensor responsible for reporting compartment temperature to the control system. Without a valid thermistor signal, the refrigerator continues to run but loses precise temperature regulation. The fault most commonly originates at the P1 connector terminals 8 and 13 rather than the thermistor component itself.
How do I fix the flashing temperature display on my Norcold refrigerator?
Start by inspecting the thermistor wire assembly and the P1 connector at terminals 8 and 13 for dirty, corroded, or broken connections. Clean and reseat the connector to see if the fault clears. If the connection looks good, test the thermistor wire assembly for continuity and then test the thermistor resistance to determine whether the sensor itself needs replacement.
Will resetting my Norcold refrigerator clear the flashing temperature setting fault?
A reset may temporarily clear the display, but the fault will return if the underlying thermistor circuit problem is not corrected. Because the code indicates an actual sensor or wiring failure, the root cause at the P1 connector or thermistor must be diagnosed and repaired to achieve a lasting fix. Resetting without addressing the fault leaves the refrigerator operating in BOS mode without accurate temperature control.
Is it safe to use my Norcold refrigerator while the temperature setting is flashing?
The refrigerator will continue to operate in Backup Operating System (BOS) mode with the fault active, but it cannot accurately regulate compartment temperature without a functioning thermistor. Food safety may be compromised if the unit runs too warm or too cold without proper feedback control. It is advisable to diagnose and repair the fault promptly rather than relying on BOS mode for extended operation.
How much does it cost to repair a Norcold refrigerator thermistor fault?
If the fix is simply cleaning or reseating the P1 connector, the repair may cost little to nothing beyond your time. Replacing the thermistor wire assembly is generally an inexpensive repair, with parts typically ranging from around 15 to 60 dollars depending on the specific assembly. If the control board is determined to be the cause, board replacement is significantly more expensive, often ranging from 150 to 400 dollars or more for parts alone.

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