Trying to replace serpintine belt but air conditioner pulley seems to sit lower than it does on diagram

Odds are you can't. The ac compressor is mounted in the belt routing so it would need the pulley to keep the belt tight.
You can get a used compressor from a salvage yard and mount it in place of your old part if necessary. It will allow the belt to run even if it has no freon in the system.
There are a few vehicles that a replacement dummy pulley was designed for, but I am not aware of one for your vehicle. Usually if you try to run the belt without the compressor pulley, it will rub against something or not allow the belt to run in the right direction.

You need to replace the compressor with a A/C compressor by-pass pulley, Part Number: 34150 autozone $28

if the ac is not working then if you leave it switched off there will be no need to get a special belt to by-pass it. The pulley on the ac compressor is just an idler pulley that only turns the compressor when there is current to the clutch in the pulley. IF you never use the ac the pulley just spins . The problem with special belts is if they fail (and they do ) it will be where/ when you cannot get a special belt but you will always get a proper belt from any spares store or garage.

You have to get an air con eliminator, it is an idler pulley than mounts in place of your air conditioner, it you change the direction of the serpentine belt you can change directions of all your major components

There is no need to remove any bolts from the engine. It is usually easiest to raise the vehicle and remove the right front tire and the plastic splash shield to gain access to the lower engine pullies. It is a TIGHT FIT getting the belts in between the pullies and the fender. All I can say to that is "welcome to the wonderful world of auto repair! - NOW maybe you have a clue why we mechanics charge so much to do seemingly simple things like "just" replacing a little sepentine belt?"
Hopefully, the routing diagram below will help you to get the belts back on correctly.

Only you could tell for sure, but try this-remove the belt and turn the compressor pulley by hand-is it real tight, lots of drag? there should be virtually no drag, if there is that is your problem-while it is off, check the other pulleys as well, all should turn easily except for the crank pulley, of course-check the water pump, alternator, power steering and if it has an air pump, check it too.

Hi.

The diagram and routing of the serpentine belt depends on the engine and on the fact if the AC is present or not. Below the diagram for the 1997-1999 110Hp US engines:

Without air conditioner:



With air conditioner:



Gain access to the belt, remove the covers, undo tensioner and start removing from lower pulley.

Regards.

Ginko.

The serpentine belt routing diagram for 2003 VW Passat V5 2.3 liter


CS = Crankshaft
F = Fan pulley
Gen = Alternator
G = Guide pulley
T = Tensioner pulley
AC = Air Conditioning
PAS = Power Assisted Steering

The serpentine belt diagram for 2001 aud A6 Quattro 2.8 liters V6 engine:


CS = Crankshaft
F = Fan pulley
Gen = Alternator
T = Tensioner
AC = Air Conditioning
PAS = Power Assisted Steering

There is a idler wheel that has a bolt that when loosened will cause it to spring back. As you lay under the car with your feet first inward ( looking straight up from under vehicle snake the belt through and over the pulleys then pry back with a long pry bar the idler pulley lever after loosening bolt on wheel or lever as you put the belt over the pulleys. I have done this belt on a 1999 528 i it is a unpleasant job without a diagram showing the serpentine pulley arrangement, there is a second idler pulley located slightly higher than the release locking idler pulley don't confuse the two, I would advise aquiring a serpentine belt diagram (cd repair manual on ebay motors) unless you are confident you can figure it out through trial and error.