Written by
Elena Vasquez Appliance Care EditorPublished October 26, 2026
VERIFIED
Error codeZone T / Amb Thrm
ApplianceIce Maker
Three thermistor messages, one instruction
These entries sit in the troubleshooting table of the U-3018CLRS-40B, a present-day clear ice machine from the 3000 line. The answer given for every one is Customer Care.
Zone T Open: an open circuit on the thermistor for either zone, left or right.
Zone T Short: a shorted circuit on that same zone thermistor.
Amb Thrm Open: an open circuit on the thermistor that reads room temperature.
Nothing for the owner to try
No checks are listed ahead of that contact. Inside the service menu, the All Errors screen tallies how many times each message has come up.
Other entries worth a look
No Comm: the unit lost communication with the display.
Slow flash: the sensor-fault LED pattern on older machines.
Ring (415) 329-7078 to ask about U-Line ice maker repair in San Francisco and the surrounding Bay Area. Name which of the three messages is showing and read out the model number.
Model compatibility: U-Line reuses codes across series and model years, so Zone T / Amb Thrm may mean something different on another appliance or generation. Confirm this against your model’s documentation and record your full model number before acting.
Plain language
What this code means
Zone T Open, Zone T Short and Amb Thrm Open: left or right zone thermistor, or ambient thermistor, circuit open or shorted; contact Customer Care.
Important safety warning. Do not attempt repairs involving electrical components, gas, water lines, refrigerant or sealed systems. Unplug the appliance if it is safe to reach the outlet, and leave internal diagnostics to a qualified technician.
Seeing this code on your U-Line appliance?
Book a specialist visit for a clear estimate and approval before any repair.
You submit a request with your appliance model and symptom, we confirm an appointment window, and a technician performs an on-site diagnosis. You then receive a clear estimate and decide whether to proceed before any repair begins.
Yes. We provide an upfront estimate after diagnosis. No parts are ordered or installed until you approve the work, so there are no surprise charges.
Replacement parts are selected for the exact model and confirmed with you before ordering or installation.
Service areas are listed on the Locations page. Contact us with your ZIP code to confirm current coverage for your address.
Ready to get your U-Line appliance working again?
Book a repair online or call us — clear estimates and approval before any repair work begins.
