Amana Refrigerator Error Code Open Thermistor Detect

This error means the control system has detected an open circuit in the freezer or refrigerator thermistor circuit. The thermistor is a temperature sensor that sends resistance-based readings to the low voltage board so the refrigerator can regulate cooling. When that circuit is broken due to a bad sensor, damaged wiring, or a failed board, indicator lights 4 through 7 will sequence as a warning alert.

Pressing Alarm Off will stop the sequencing indicator lights and silence the visual alert, but it does not fix the underlying fault. The error will return if the open circuit condition in the thermistor wiring or the board is not corrected. The Alarm Off button is intended to acknowledge the alert, not to clear the root cause.

Repair costs vary depending on which component has failed. A replacement thermistor is generally an inexpensive part, typically in the range of $15 to $50 for the part alone. Wiring repairs may cost little if only a connector needs cleaning, or more if a section of harness must be replaced. Low voltage board replacement is the most expensive scenario, with parts potentially ranging from $80 to $200 or more, plus labor if a technician performs the work.

Start by checking the resistance values at each thermistor with a multimeter and comparing them to the expected range for the current cabinet temperature. Next, test the wiring harness for continuity from the thermistor connectors all the way to the low voltage board. If the thermistor reads open or infinite resistance, replace it. If the wiring is broken or corroded, repair or replace the affected section. If both components test correctly, the low voltage board may need to be replaced.

Continued use carries some risk because the control board may not be able to accurately monitor or regulate internal temperatures without a functioning thermistor circuit. Food safety could be compromised if the refrigerator or freezer drifts outside of safe temperature ranges without triggering the appropriate cooling response. It is best to address the repair promptly and monitor compartment temperatures with a separate thermometer in the meantime.