Freezer displays E1 and may not maintain set temperature; alarm may sound intermittently.

Safety first: Unplug the freezer or switch off the dedicated circuit breaker before removing any panels.

Step-by-step checks:

• Power reset: Disconnect power for 5 minutes, then restore power to see if the E1 code clears. If it returns, continue.
• Locate the cabinet/evaporator thermistor: On most Monogram freezers, the temperature sensor is clipped to the evaporator tubing behind the rear interior panel or in the air return channel.
• Inspect wiring: Remove the interior rear panel (usually Phillips screws). Check the thermistor leads for cuts, pinches, or corrosion at the connector. Reseat the connector firmly.
• Resistance test: With the unit unplugged, disconnect the thermistor from the harness. Using a multimeter, measure resistance at freezer temperature (around 0°F / -18°C). A typical NTC thermistor should read roughly 16–30 kΩ at that temperature (consult Monogram service data if available). If it reads open (OL) or near 0 Ω, it is defective.
• Check at the main board: Access the main control board (often behind a rear lower access panel). Verify continuity from the thermistor connector to the board pins to rule out a broken harness.
• Replace if faulty: If readings are out of range, replace the evaporator/cabinet thermistor. Clip the new sensor in the same location and route wiring away from sharp edges and moving parts.

When to call a technician: If the thermistor and wiring test good, the main control board may not be reading the sensor correctly and should be diagnosed or replaced by a professional.