I need to find the fuse location for the headlamps on a 1999 Audi 2.8 A4 Quattro? Can you help?

You make it sound like it's our fault you can't find it :>D

The start of production of the Audi A4 B5 is 1994. With minor changes, it was produced until 2001. At first, only the sedan version was available, the station wagon (Avant) appeared a year later. This material provides information on relay circuits and fuses Audi A4 b5 1994, 1995, 1996, 1997, 1998, 1999, 2000, with an assignment of their elements and locations.

Can't get much clearer than this. Relay 4 is one plus 'Additional Relays 23 and 24. Plus fuse 23 and 24.

Fuse box diagram Audi A4 B5 and relay with assignment ...

https://fuseandrelay.com > audi > a4-b5

This material provides information on relay circuits and fuses Audi A4 b5 1994, 1995, 1996, 1997, 1998, 1999, 2000, with an assignment of their elements and ...
‎Passenger compartment · ‎Main fuse box · ‎Relay box · ‎Engine compartment

its in your owners manual and on cover of fuse/relay covers https://www.manualslib.com/manual/396576/Audi-A4.html

don't think fuse diagram will help , is the battery in good condition , may not hold enough charge to turn over engine , try jump start if engine starts then get a new battery then check alternator charge rate as may be reason battery went

141 o2 sensor heater, bank 1, sensor 2

I think that the best windshield wiper for 1999 Audi A4 Quattro is BOSCH AEROTWIN (530 mm) - New type with one single rubber blade!

I have 1999 Audi A4 2,8 quattro water is permanently leaking from the reservouir(or radiator?) and I have to add it every two weeks. What's the solution?

For Audi A4 the fuse box is located on the left side of dashboard behind a plastic cover (for left hand steering wheel vehicle). On inner face of the plastic cover you will find the fuse diagram.
First fuse on first row from left upper corner is Fuse Nr.20 = F20 (15A) - RH headlamp low beam, headlamp adjustment.
First fuse on second row from left upper corner is Fuse Nr.21 = F21 (15A) - LH headlamp low beam, headlamp adjustment.

For Audi A4 the fuse box is located on the left side of dashboard behind a plastic cover (for left hand steering wheel vehicle). On inner face of the plastic cover you will find the fuse diagram.
First fuse on first row from left upper corner is Fuse Nr.20 = F20 (15A) - RH headlamp low beam, headlamp adjustment.
First fuse on second row from left upper corner is Fuse Nr.21 = F21 (15A) - LH headlamp low beam, headlamp adjustment.

when you pull the fuse door of there is sometimes a diagram on the door itself, if not then check the owners manual. if neither of those then get yourself a chiltons manual

Here is a manual, but you have to purchase it:

http://shopping.msn.com/prices/audi-a4-service-manual-1-8l-turbo-2-8l-including-avant-and-quattro/itemid2373553/?itemtext=itemname:audi-a4-service-manual-1-8l-turbo-2-8l-including-avant-and-quattro