mypros+
Error code reference

U-Line Ice Maker Error Code Amb Thrm Short

Ambient thermistor circuit is shorted.

U-Line codesU-Line ice maker codes

Ambient thermistor circuit is shorted.

First step from the service manual

Inspect thermistor cable for pinch points or damage. Replace if necessary.

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 Amb Thrm Short.

  • 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 Amb Thrm Short means on a U-Line ice maker

The Amb Thrm Short error code on a U-Line ice maker indicates that the ambient thermistor circuit has developed a short condition. The ambient thermistor is a temperature-sensing resistor responsible for monitoring the air temperature surrounding the ice maker. When the control board detects a shorted circuit in this thermistor loop, it triggers this fault because the measured resistance has dropped below the expected range, sending an inaccurate low-resistance signal that the board interprets as a shorted sensor or wiring path.

A shorted thermistor circuit typically presents itself through abnormally low resistance readings across the thermistor terminals. Under normal operating conditions, a thermistor produces a predictable resistance value that varies with temperature. A short causes the resistance to collapse toward zero ohms, which corrupts temperature data and prevents the unit from making accurate operational decisions based on ambient conditions. The fault can originate at the thermistor component itself or anywhere along the cable connecting it to the control board.

The first diagnostic step is a physical inspection of the thermistor cable for pinch points, cuts, or areas where the insulation has been compromised. Cables routed near sharp metal edges, moving components, or areas subject to ice buildup are particularly vulnerable. If the cable insulation is breached and conductors contact each other or a grounded surface, a short circuit results. After confirming cable integrity, resistance testing of the thermistor itself will confirm whether the component requires replacement.

Source: manufacturer service documentation.

Common causes of Amb Thrm Short

  1. 01

    Damaged or pinched thermistor cable

    Part replacement

    The wiring harness connecting the ambient thermistor to the control board may be pinched against a cabinet edge, hinge point, or internal component, causing the insulation to fail and the conductors to short together. Inspect the full length of the cable for visible kinks, cuts, or crush points.

  2. 02

    Failed ambient thermistor

    Part replacement

    The thermistor component itself can fail internally, resulting in a shorted condition even when the cable appears undamaged. Resistance testing across the thermistor terminals will reveal a near-zero reading if the component has failed.

  3. 03

    Moisture or ice intrusion on the connector

    Wiring / connection

    Water or ice accumulation at the thermistor connector can bridge the terminals and create a low-resistance path that mimics a short circuit. Inspect the connector for corrosion, moisture, or ice buildup and dry or clean it thoroughly before retesting.

  4. 04

    Chafed cable insulation contacting a ground

    Part replacement

    If the thermistor cable insulation has worn through at any point where the cable contacts the metal chassis, a short to ground can occur. Look for areas where the cable runs near sheet metal edges without adequate protection.

  5. 05

    Control board input fault

    Part replacement

    In rare cases the thermistor input circuit on the control board itself may be damaged, causing it to read a good thermistor as shorted. This is typically diagnosed only after confirming the thermistor and cable both test within normal parameters.

See the test procedure for each cause

Frequently asked questions about Amb Thrm Short

What does Amb Thrm Short mean on a U-Line ice_maker?
Amb Thrm Short means the ambient thermistor circuit has been detected as shorted by the control board. The ambient thermistor monitors surrounding air temperature and feeds that data to the control system. A shorted circuit produces an abnormally low resistance reading that the board cannot use for accurate temperature control. The fault can be caused by damaged wiring, a failed thermistor, or moisture at the connector.
Can I fix the Amb Thrm Short error myself?
A knowledgeable DIYer can begin by inspecting the thermistor cable for visible damage, pinch points, or moisture at the connector, which are the most common causes. If the cable looks intact, using a multimeter to test thermistor resistance can confirm whether the component itself has failed. Replacing the thermistor or its cable is a straightforward repair if you are comfortable working with appliance wiring, but if the control board is suspect, professional service is recommended.
Is it safe to continue using my U-Line ice maker when this error is showing?
It is generally not advisable to continue relying on the ice maker while this error is active. Without accurate ambient temperature data, the control system may not operate efficiently or may make incorrect decisions about the cooling and ice-making cycle. Continuing to run the unit in this state could lead to poor ice production or additional component stress.
How much does it cost to repair the Amb Thrm Short error on a U-Line ice maker?
If only the thermistor or its cable requires replacement, repair costs are typically in the range of $50 to $150 for parts and labor, depending on your location and service provider. If the control board is found to be the root cause, costs can rise significantly, often falling in the $200 to $400 range or higher. Getting a diagnostic visit from a qualified technician will give you a firm estimate before committing to the repair.
Will resetting my U-Line ice maker clear the Amb Thrm Short error?
A reset may temporarily clear the error code from the display, but if the underlying short condition still exists in the thermistor circuit, the fault will return once the unit runs through its diagnostic cycle again. Clearing the code without addressing the root cause does not fix the problem. The thermistor, cable, and connectors must be inspected and tested to achieve a lasting repair.

Related U-Line ice maker codes

All U-Line ice maker codes
View all 61 U-Line ice maker codes

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

Get Started

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

    U-Line Amb Thrm Short Error Code: Ambient thermistor circuit is shorted. | MyPros+