Ice maker will not power on, display shows E1 shortly after plugging in.

Safety first: Unplug the Summit ice maker from the wall outlet before removing any panels. Water and electricity are a dangerous combination.

Step-by-step checks:

• Power reset: Unplug the unit for 5 minutes, then plug it back in to see if E1 clears. If it returns, continue.
• Locate the cabinet temperature sensor: On most Summit undercounter and freestanding ice makers, the cabinet/ambient NTC sensor is clipped to the evaporator plate area or mounted on the liner wall behind an access cover. Remove the front lower kick plate or rear panel as needed.
• Inspect the sensor and wiring: Look for broken insulation, corroded connectors, or a sensor probe that has come loose from its mounting clip. Reseat any loose connectors on the sensor harness and on the main control board.
• Test the sensor (if you have a multimeter): Disconnect the sensor from the harness and measure resistance at room temperature. A typical NTC sensor will read between 5–20 kΩ at ~25°C. If it reads open (OL) or 0 Ω (shorted), the sensor is bad.
• Replace the sensor if faulty: Order a compatible cabinet temperature sensor / NTC probe for your specific Summit model. Route the new sensor along the original path, secure it with clips, and reconnect to the control board.
• If sensor tests good: The fault may be in the control board’s sensor input circuit. Inspect the board for burn marks or corrosion. If present, replace the main control board.

When to call a technician: If you are not comfortable testing resistance or accessing internal wiring, or if replacing the sensor does not clear E1, contact a qualified appliance technician.