How do you change a bulb on an Audi A3 1999 Air control?

To change the bulb on the air control of a 1999 Audi A3, first, ensure the vehicle is turned off and the keys are removed from the ignition. Remove the surrounding trim and gently pull out the air control unit from the dashboard. Locate the bulb holder at the back, twist it counterclockwise to release, and replace the old bulb with a new one. Finally, reassemble the unit and trim, ensuring everything is securely in place.