Display shows E3; freezer may run erratically or not reach set temperature; sometimes interior fan behavior is abnormal.

Safety first: Disconnect mains power before opening the control panel or display housing.

Step-by-step checks:

• 1. Confirm installation conditions: Ensure the freezer is not installed in an unheated garage or very hot room outside the specified ambient range; extreme ambient can trigger sensor-related errors.
• 2. Access control housing: Remove the screws securing the top/front control panel where the display and buttons are located. Carefully pull the panel forward.
• 3. Locate ambient sensor: The ambient NTC is often positioned near the air intake of the control housing or behind the display board, sometimes in a small plastic tube or clip.
• 4. Inspect wiring and connector: Check for loose plugs, damaged insulation, or corrosion. Reseat the connector to the PCB.
• 5. Measure sensor resistance: Disconnect the sensor and test with a multimeter. Compare to typical NTC values at room temperature. Replace if open, shorted, or far out of range.
• 6. Check PCB: If the sensor and wiring are good, inspect the display/control PCB for burnt components or corrosion. If E3 persists, the PCB may be defective and require replacement.

When to call a technician: If you are not comfortable removing the control panel or testing components on the PCB, arrange service with an authorized Gram technician.