It's actually 4, and the one directly behind the indicator light is a
real bear to reach. I had to glue an extension on an Allen wrench (hex
wrench) to a socket to be able to reach it. The entire light unit pulls
forward so you can replace the bulbs. I think you could replace the
high and low beam lights without having to pull the unit out.
To get to all of the bolts, you have to remove the snorkel section of
the airbox. It attaches to the radiator support with 2 Phillips screws.
'04 A4 1.8Tq MT-6
Central NJ USA