Sub-Zero Refrigerator Error Code Steady light

On the Sub-Zero UC-15I ice machine, a steady control board light indicates that the thermistor is operating normally. This is a status confirmation, not an error or fault code. The thermistor is reading within its expected resistance range and the control board is receiving a valid temperature signal. No repair or intervention is necessary when this light is steady.

Yes, a steady control board light on the UC-15I indicates normal operation of the thermistor circuit. The machine is safe to use. This light signals that temperature monitoring is active and functioning, which is a required condition for proper ice production.

A power cycle or reset of the UC-15I will not eliminate the steady light if the thermistor continues to operate normally, because the light reflects real-time thermistor status rather than a stored fault. After the reset, if the thermistor is still reading correctly, the steady light will return. Only a thermistor fault would cause the indicator to behave differently.

No repair is needed when the control board shows a steady light. This indicator confirms normal thermistor function on the UC-15I ice machine. If you are experiencing ice production problems despite the steady light, the issue lies in a different component and the thermistor can be eliminated as a suspect.

A steady light requires no corrective action and therefore involves no parts or repair cost. If a technician is called to diagnose an unrelated ice production issue on the same unit, a typical service call for a Sub-Zero appliance may range from $100 to $250 or more depending on your region and the nature of any additional repairs needed.