Insignia upright or chest freezer beeps and displays E1; temperature may not be accurate or may fluctuate.

Safety first: Unplug the freezer before removing any panels or handling wiring. Use a non-contact voltage tester if available.

Step-by-step:

• Power reset: Unplug the freezer for 5 minutes, then plug back in. If E1 clears and does not return, it may have been a transient fault.
• Locate the thermistor: On most Insignia freezers, the cabinet thermistor is behind a small plastic cover on the interior liner (often near the evaporator cover or side wall). Remove the cover carefully.
• Inspect the sensor and wiring: Check for broken, pinched, or chewed wires, loose connectors, or corrosion. Reseat the connector firmly at the sensor and at the main control board (usually behind the rear or top control panel).
• Test the thermistor: With a multimeter set to resistance (ohms), measure across the thermistor leads. At room temperature (~77°F / 25°C), most Insignia NTC thermistors will read roughly 5k–10kΩ. If it reads open (OL) or 0Ω, it is defective.
• Replace if faulty: If readings are out of range or intermittent when you gently wiggle the wires, replace the cabinet temperature sensor (thermistor). Route the new sensor along the original path and secure it away from moving parts or sharp edges.
• Check the control board: If a known-good thermistor is installed and wiring is intact but E1 persists, the main control board thermistor circuit may be defective and should be replaced. This is typically behind the control panel or rear service cover.

When to call a technician: If you are not comfortable testing resistance or accessing the control board, or if the new thermistor does not clear the error, contact a qualified appliance technician.