Interior temperature fluctuates widely when the room temperature changes.

Safety: Unplug the unit before accessing sensors.

• Relocate if necessary: Move the cooler away from ovens, dishwashers, or direct sunlight.
• Check ambient sensor: On models with an ambient thermistor, inspect and test it as described in the E3 entry. Replace if faulty.
• Inspect cabinet for damage: Look for dents or damage that may have compromised insulation.
• Monitor with a thermometer: Use an independent thermometer to verify actual swings and adjust setpoint accordingly.
• Control board replacement: If sensors and installation are correct but swings remain extreme, the control board may not be compensating properly and may need replacement.