Audi wallbox makes a loud buzzing or humming noise during charging.

Safety first: Noise alone is not necessarily dangerous, but if accompanied by smell or heat, stop using the charger.

• Characterize the noise: Determine if the noise is constant or only when charging starts. A single click is normal; continuous loud buzzing is not.
• Check mounting: With power off, remove the cover and ensure the main contactor and any transformers/inductors are firmly mounted and not touching the housing.
• Inspect contactor: Look for signs of wear or burning on the contactor. If the armature is not closing fully, it can buzz; replace the contactor.
• Supply quality check: An electrician can measure THD (total harmonic distortion) or check for severe voltage imbalance that may increase noise. Address supply issues if present.

If noise is excessive or worsening, replace the noisy component to prevent eventual failure.