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Error code reference

U-Line Ice Maker Error Code Amb Thrm Open

Ambient thermistor circuit is open.

U-Line codesU-Line ice maker codes
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What the Amb Thrm Open error code actually means

Your U-Line ice maker has detected a problem with the sensor that measures the temperature of the air around the unit. The sensor or its wiring has lost electrical continuity, so the machine cannot get an accurate temperature reading and has stopped normal operation. Checking the sensor's wiring connection or replacing the sensor itself is usually what fixes this issue.

Diagnostic procedure

The full Amb Thrm Open procedure

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1
First diagnostic step
Inspect ambient thermistor connection. Replace if necessary.
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Most common causes of Amb Thrm Open

Ranked by how often they cause this code
  1. 1Loose or disconnected thermistor connector
  2. 2Failed ambient thermistor
  3. 3Damaged or broken wiring harness
  4. 4Corroded connector terminals
  5. 5Control board fault

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Questions people ask about Amb Thrm Open

What does Amb Thrm Open mean on a U-Line ice_maker?
Amb Thrm Open indicates that the ambient thermistor circuit is open, meaning the control board is not receiving a valid resistance signal from the sensor that monitors surrounding air temperature. This could be caused by a disconnected wiring connector, a broken wire, or a failed thermistor. The unit will not operate normally until the fault is resolved.
Is it safe to continue using my U-Line ice maker while this error is displayed?
You should not attempt to bypass this error or continue running the unit in a fault state. The ambient thermistor provides temperature data the control board uses to time ice production cycles correctly, and operating without it could lead to improper cycling or component stress. Resolve the fault before resuming normal use.
How much does it cost to repair the Amb Thrm Open error on a U-Line ice maker?
If only the thermistor needs replacement, parts typically range from around $15 to $60 depending on the specific model. If professional service is needed, total repair costs including labor generally fall in the $100 to $250 range. Diagnosing and reseating a loose connector yourself costs nothing beyond your time.
Can I fix the Amb Thrm Open error myself?
If the cause is a loose connector, reseating it is a straightforward repair that most DIYers can handle. If the thermistor itself has failed, replacing it requires basic electrical knowledge and the correct replacement part. Start by inspecting the connector and wiring before ordering any parts.
Will resetting my U-Line ice maker clear the Amb Thrm Open error?
A reset may temporarily clear the error code, but it will return as soon as the control board scans the thermistor circuit again and detects the open condition. The underlying cause, whether a disconnected connector, broken wire, or failed thermistor, must be physically corrected before the error will stay cleared.

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