How to Replace an Audi Bulb
1. Open the hood and examine the area behind the headlights or front turn signals. You should see where the wires go into the back of the bulbs.
2. Remove the cover for the headlight housing, if there is one. This will be held on either with snaps or a couple of Phillips-head screws.
3. On some models, such as the A4, you must remove the air intake duct on the passenger side to gain access to the bulb. This is held on with two Torx screws on top of the duct.
4. Remove the two or three screws that hold the top of the headlight housing in place. Loosen--but do not remove--the screws that hold the bottom into place.
5. Gently push the headlight forward to gain access to the bulbs.
6. Unclip the wire clip that holds the bulb into the housing, and pull out the bulb and harness.
7. Install the new bulb in the reverse of removal.
8. Open the trunk (on a sedan) or the hatch (on a wagon), and inspect the area behind the taillights and rear turn-signal housings. There will be a small, round plug in the back of the housing that conceals the screw for the housing.
9. Pry the housing cover out with a thin screwdriver, and remove the screw.
10. Pull the taillight housing away from the body of the car. You may have to move some of the rubber seal that goes over the housing to be able to pull it out.
11. Separate the panel that holds the bulbs from the back of the housing.
12. Press down gently on the bulb, and turn the bulb to release it.
13. Install the new bulb and replace the pieces in the reverse of removal.