If you have a squeaky HVAC blower in your C5 A6, you know how annoying it can be in the otherwise quiet and tranquil cabin. Luckily, replacing it with a new one is not all that difficult, and for the really mechanically inclined, it's not hard to put a dab or two of oil on the bearings and clean the gunk out of the motor.
Step One: Remove the glove box. There are only 5 8mm head bolts that hold the whole thing to the dash.
Once you remove the bolts, you can lower the glove box to the floor. You'll be looking at the HVAC box, among other things. The round case you see is the blower fan. You can pop the access hole cover off, and spray a little lube in there, and see if that eliminated the squeak. If not, move on to replacing blower motor, or for the brave, pull it apart, and clean and lube it.
Unbolt the 3 screws (you can use a Torx, or a flat blade screwdriver).
Using your harness connector tool of choice to remove the contacts from the harness connector on the body of the motor case. This is required, as they aren't long enough to pull the motor out when in place. The rubber cover just pulls off.
Unscrew the 2 Torx screws on either side of the access hole. You should now be able to pull the motor out of the housing. I used electrical parts cleaner to clean the motor from my car, lubed the bearing on the outer end, and moved on to pulling the fan off. I'm not sure if it's needed or not, but I used a hammer to drive the shaft out of the fan. I think I hit it too hard though, which seemed to push the shaft out of alignment. I had to fiddle with it to get the shaft happy again. If I had to to it again, I'd probably leave the fan on the shaft, and just spray some lube in the general direction of the shaft.
And here is the result of the taps with the hammer. Yes, that all came out of the motor, before any cleaner.
The squeaks are gone from my fan, it's much quieter overall..