There are two ways to enable the ventilation of the seats on the Mercedes S-class (W221):
1. Place the key in position 1 or 2. Push the button (1) on the door and hold it until the proper ventilation is installed (three levels of blue indicators are available).
2. Enabling the comfortable opening function. It can be used to drive the car before the beginning of the movement. All glass, escape hatch and the driver's seat ventilation system is activated. To enable the function, press and hold the door unlock button on the key.