Freezer displays error code A3 and may intermittently stop cooling or show erratic temperature readings.

Safety first: Disconnect the freezer from mains power before removing any internal panels.

• Locate the sensor: On many Ariston no-frost freezers, the evaporator NTC is clipped to or near the evaporator behind the internal rear panel of the freezer compartment.
• Visual inspection: Remove drawers and the rear inner panel (usually held by screws). Look for a small sensor probe with two wires. Check for broken wires, corrosion on connectors, or signs of moisture damage.
• Check connections: Reseat any plug connectors going from the sensor to the wiring harness. Ensure they are firmly locked.
• Basic resistance check (for advanced DIYers): With the sensor disconnected and the freezer at room temperature, measure resistance with a multimeter. Typical NTC sensors read between 5–20 kΩ at 25°C (exact value depends on model). A reading of 0 Ω (short) or infinite (open) indicates a bad sensor.
• Replace if faulty: If the sensor is clearly damaged or readings are out of range, replace it with an Ariston-compatible evaporator NTC sensor. Reassemble panels carefully to avoid air leaks.

When to call a technician: If the sensor tests good but the A3 error persists, the main control board may be defective and should be checked by a professional.