BMW Noisy Contactor / Coil Hum

BMW EV charger makes loud buzzing or clicking noises during operation

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Safety Warning

This repair may involve working with high voltage components or water connections. Always unplug the appliance before removing any panels.

If you are not confident in your ability to perform this repair safely, we strongly recommend contacting a professional technician.

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Possible Causes

Aging or loose main contactor in BMW Wallbox, Supply voltage imbalance causing coil hum, Loose mounting of contactor or transformer, Foreign object vibrating against housing

How to Fix / Troubleshooting

Safety first: Turn off the breaker before touching the Wallbox. Do not insert tools into the housing.

  • Identify noise source: Stand near the Wallbox while it operates to determine if the noise is from inside the unit or from the cable/plug area.
  • Check mounting: Ensure the Wallbox is firmly attached to the wall and not vibrating against loose siding or panels.
  • Listen for abnormal patterns: Occasional clicks at start/stop are normal; continuous loud buzzing is not.

If the noise is clearly from inside the unit and is new or unusually loud, the contactor or transformer may be failing. A BMW-authorized technician should open the unit, tighten mounting hardware, and replace noisy components if necessary.

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Repair Difficulty

Medium 3/5

Required Part

BMW Wallbox Main Contactor / Internal Transformer
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