If the seat ventilation is deactivated via the switch or due to parking the vehicle, the fans in the seat...
BMW technical service bulletin B521125 for 2020-2025 BMW 840I.
- Bulletin number
- B521125
- Component
- Seats
- Summary
- If the seat ventilation is deactivated via the switch or due to parking the vehicle, the fans in the seat cushionor under the seat cushion surface are unpleasantly loud. The fans speed up loudly twice and then turn off. The functionality of the fans is not impaired. This behavior only occurs after the vehicle had been programmed to I level S18A- 25-07-520 and higher; upto, but not including S18A- 25-07-551.
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