If you mean the headlight bulbs on the A4 then you have to remove the headlight unit from the car.
To do this remove the 2 torx screws from the top of the unit. If you then look down the back of the unit you will see another torx screw at the bottom. You need to loosen this (do not remove it). You can then disconnect the wiring plug and slide the light unit out of the car. Replacement is the reverse of the removal. You may need to wiggle the unit about a bit to get in out and back in again
Note on the right hand light you will have to remove the air intake trunking (very easy)
Hope this helps.
Audi UK charges £32 to change a headlight bulb
I have a 97a4, and i didnt have to remove the units. Just pull the rear covers off and unplug the bulbs. Then u pushed in on the metal retaining clips. My bulbs then came right out and i reversed the process to put them back in. I reccomend removing part of the intake pipe on the passengerside, that helps alot.
A forum community dedicated to all Audi model owners and enthusiasts. Come join the discussion about performance, maintenance, troubleshooting, modifications, classifieds, and more for your favorite models!