you unscrew the light bulb and put another one in from auto zone. There sholud also be a manual that came with the car (alternatively see if you can find it online) which should help you with the work.
To replace the headlight bulbs in a 2007 Audi A6, first, open the hood and locate the back of the headlight assembly. Disconnect the electrical connector from the old bulb and remove the bulb by twisting it counterclockwise. Insert the new bulb, ensuring it is securely in place, and reconnect the electrical connector. Finally, test the new bulb before closing the hood.
Pull the carpeting behind the brake light. Unclip the assembly, replace bulb.
To change a side light bulb on an Audi TT, remove the light lens by unscrewing the screws holding it on. Then, remove the old bulb and insert a new one. Replace the cover and tighten the screws.
To replace the brake light bulb on a 2005 Audi A6, first, open the trunk and locate the rear light assembly. Remove the access cover or screws securing the light assembly, then gently pull it out. Twist the bulb holder counterclockwise to release it, replace the old bulb with a new one, and reassemble by reversing the steps. Ensure the assembly is securely in place and test the new bulb before closing the trunk.
To replace the tail light bulb on a 2008 Audi A6, start by opening the trunk and removing the access panel or cover located behind the tail light assembly. Once exposed, twist and remove the bulb holder from the assembly, then pull out the old bulb and replace it with a new one, ensuring it clicks into place. Reinsert the bulb holder back into the assembly, replace the access panel, and test the new bulb to confirm it’s functioning.
To change the center brake light on a 2007 Audi A4 Quattro, start by opening the trunk and removing the plastic cover or trim panel that conceals the brake light assembly. Next, locate the brake light bulb holder, twist it counterclockwise to release it, and remove the old bulb. Replace it with a new bulb, reassemble the holder, and snap the cover or trim panel back into place. Finally, test the brake light to ensure it’s functioning correctly.
To replace the rear bulb on an Audi A3, first, open the trunk and locate the access panel behind the rear light assembly. Remove the panel or the screws securing the light assembly, then gently pull it out. Disconnect the bulb holder by twisting it counterclockwise, replace the old bulb with a new one, and reassemble the light assembly by reversing the steps. Ensure the new bulb is securely in place and test it before closing everything up.
To replace the glove compartment light bulb on a 2002 Audi A4, first open the glove compartment and remove any contents. Locate the light bulb cover, which is usually on the back of the glove compartment. Gently pry off the cover, then remove the old bulb by twisting it counterclockwise. Insert the new bulb, replace the cover, and ensure it’s secure before closing the glove compartment.
It is not a serviceable part.
To replace the brake light bulb on an Audi A3, first, open the trunk and locate the tail light assembly. Remove the appropriate access panel or cover, then twist the bulb socket counterclockwise to release it. Pull out the old bulb and insert the new one, ensuring it's securely in place, then reassemble the socket and cover. Finally, test the brake light to ensure it's functioning properly.
To change the reversing light bulb on an Audi A3, first, ensure the vehicle is turned off and the key is removed. Locate the rear light assembly by opening the trunk and removing any covers if necessary. Twist or unclip the bulb holder to access the reversing light bulb, then pull it out and replace it with a new bulb. Finally, reassemble the light assembly and test the new bulb to ensure it works properly.
I've written it up here... http://samboutros.wordpress.com/2007/04/02/2003-audi-a4-bulb-replacement/ Steps, pictures and links to bulbs...