mypros+
Error code reference

Norcold Refrigerator Error Code 13

Thermistor failure; unit is being controlled by backup operating system (BOS).

Norcold codesNorcold refrigerator codes

Thermistor failure; unit is being controlled by backup operating system (BOS).

First step from the service manual

Check if thermistor is present and connected correctly.

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

MyPros+ Max

Get the full diagnostic procedure for 13.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What 13 means on a Norcold refrigerator

Error code 13 on a Norcold refrigerator indicates a thermistor failure. The thermistor is a temperature-sensing resistor that provides real-time thermal feedback to the control board, allowing the unit to regulate cooling cycles accurately. When the control board detects that the thermistor signal is absent, out of range, or inconsistent, it logs code 13 and switches operation over to the Backup Operating System (BOS). The BOS allows the refrigerator to continue running at a fixed, predetermined cooling rate without active temperature feedback, which means temperature regulation will be less precise than normal.

The thermistor itself is a small, passive component typically mounted inside the refrigerator compartment. Its resistance changes predictably with temperature, and the control board interprets these resistance changes as temperature readings. A failure can stem from a broken thermistor element, a disconnected or corroded connector, damaged wiring in the thermistor harness, or in some cases a faulty control board that cannot correctly read an otherwise functional thermistor signal.

The first diagnostic step is to confirm the thermistor is physically present and that its connector is fully seated and free of corrosion or damage. If the thermistor is connected and intact, resistance testing of the thermistor element can help determine whether the component itself has failed. A thermistor reading that is open-circuit, short-circuit, or grossly out of specification for the ambient temperature confirms the sensor needs replacement. Until the fault is resolved, the unit will continue operating under BOS control.

Source: manufacturer service documentation.

Common causes of 13

  1. 01

    Disconnected thermistor connector

    Wiring / connection

    The thermistor wiring harness connector may have come loose from the control board or the thermistor itself. Inspect both ends of the connector for proper seating and secure attachment.

  2. 02

    Failed thermistor element

    Part replacement

    The thermistor component can fail internally, resulting in an open-circuit or short-circuit reading that the control board cannot interpret as a valid temperature. Resistance testing of the thermistor will confirm whether it has failed.

  3. 03

    Corroded or damaged connector terminals

    Wiring / connection

    Moisture or age can corrode the thermistor connector terminals, creating high resistance or an intermittent connection. Visually inspect the connector for green or white corrosion deposits and check for bent or pushed-back pins.

  4. 04

    Damaged thermistor wiring harness

    Part replacement

    The wiring between the thermistor and the control board can be pinched, chafed, or broken, particularly where the harness passes through cabinet openings. Inspect the full length of the harness for visible damage.

  5. 05

    Faulty control board

    Part replacement

    If the thermistor and its wiring test within specification but code 13 persists, the control board's thermistor input circuit may have failed. This is the least common cause and should be considered after all other possibilities are ruled out.

See the test procedure for each cause

Frequently asked questions about 13

What does 13 mean on a Norcold refrigerator?
Error code 13 means the refrigerator's thermistor has failed or lost its connection to the control board. The thermistor is the temperature sensor that guides the cooling system. When this fault is detected, the unit automatically switches to its Backup Operating System (BOS) so it can continue running, but without accurate temperature regulation.
Can I fix error code 13 on my Norcold refrigerator myself?
The first steps are within reach of many DIYers: check that the thermistor connector is fully plugged in and free of corrosion, and inspect the wiring harness for visible damage. If the connector is secure and undamaged but the code persists, testing the thermistor's resistance with a multimeter can confirm whether it needs replacement. Replacing the thermistor is a straightforward repair, but diagnosing a faulty control board typically requires more advanced technical skill.
Is it safe to keep using my Norcold refrigerator when error code 13 is showing?
The refrigerator will continue to operate under the Backup Operating System when code 13 is active, so it is not an immediate safety hazard. However, because the BOS runs the unit without live temperature feedback, cooling performance will be less accurate and food temperatures may drift outside the ideal range. It is best to address the fault promptly to ensure reliable food preservation.
How much does it cost to repair error code 13 on a Norcold refrigerator?
If only the thermistor sensor needs replacement, parts typically cost in the range of $15 to $50 depending on the specific model, making it one of the more affordable repairs. If professional labor is involved, total repair costs could range from $75 to $200 or more. A control board replacement, if required, is significantly more expensive and can range from $150 to $400 or higher for parts alone.
Will resetting my Norcold refrigerator clear error code 13?
A reset may temporarily clear the code from the display, but if the underlying thermistor fault still exists, the code 13 will return and the unit will go back into BOS mode. A reset is not a fix for a failed or disconnected thermistor. The root cause, whether it is a loose connector, damaged wiring, or a failed thermistor element, must be corrected before the error will stay cleared.

Related Norcold refrigerator codes

All Norcold refrigerator codes
View all 107 Norcold refrigerator codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass