Synchronisation button on the driver's side temperature controls.
Press the driver's side temperature button in the centre display's climate row in order to open the controls.
Press Synchronise temperature.
The temperature for all zones in the car is synchronised with the temperature set for the driver's side and the synchronisation symbol is shown adjacent to the temperature button.
The synchronisation is stopped by means of a further press on Synchronise temperature or by means of changing the temperature settings for a climate zone other than the driver's.