U-Line Refrigerator Error Code L Evap T Open

The "L Evap T Open" error code on a U-Line refrigerator indicates that the control board has detected an open circuit in the left evaporator thermistor loop. The evaporator thermistor is a temperature-sensing resistor (thermistor) mounted near the evaporator coil. Its job is to continuously report coil temperature back to the control board so the system can regulate defrost cycles and compressor operation. When the circuit reads as open, the board receives no valid signal from that sensor, which prevents normal temperature regulation on the left side of the unit.

An open circuit in a thermistor loop typically means the electrical path between the sensor and the control board has been broken. This can occur at the thermistor itself if the sensing element has failed internally, or anywhere along the wire harness running from the sensor to the board. Connector pins that have corroded, backed out, or been damaged by moisture are a frequent source of open-circuit faults. The wiring can also be pinched, chafed, or broken, particularly in areas where the harness routes around cabinet edges or through grommets.

The first diagnostic step is to inspect the thermistor connector for secure seating, corrosion, and physical damage. If the connector is intact, resistance testing of the thermistor across its terminals will confirm whether the sensor itself has failed. A thermistor with an open internal failure will read infinite resistance rather than the expected value for its temperature range. If wiring and connectors check out, the thermistor should be replaced. Persistent faults after sensor replacement may point to a control board issue.