Max defroster raises the fan speed and temperature. Air conditioning is activated and air recirculation is unavailable while max defroster is active. When max defroster is turned off again, the climate settings return to their previous levels.
Note
When max defroster uses the high fan speed, the noise level of the fans increases.
Your car also has a heated windscreen to help remove condensation and ice.
You can activate the max defroster via both the centre display and the button panel below the centre display.
Activating via the button panel
Press the max defroster button 
once to activate the max defroster.
Press the button again to deactivate the max defroster.
Activating via the centre display
Press the fan symbol in the bottom bar 
.
.Press the max defroster symbol 
to activate the max defroster.
Press the symbol again to turn it off.