I bought this audi a6 2000 a few months ago, I replaced the battery when I bought it because it had problem starting alternator was working. since last week the battery doesn't hold it's charge more than 30 hours. So I figured out it was a parasitic drawing somewhere, put the multimeter on, 90mah. I don't know what's the standard drawing for this car but I think it's too much, I went ahead and pulled fuse one at a time, didn't do much. I pulled the relays and did nothing, then I unplugued one of the red wire near the relays under the cluster and it did drop to 40mah, I still think it's too much I don't have the wiring diagram either do I know what's that wire for. Can anyone help me out?
It may sound silly but............. In my case it was low pressure of the AC Gas. When this pressure is to low the car does something and you can hear buzzing sound all night. It will drain battery. I refilled the AC system with 12A to 50 on the low end and now I check it bimonthly.
When talking about the A/C keep in mind that this is a closed loop system and if you need frequent charge to top up the A/C you have a leak that needs to be fixed.
Bookmark
this site! 
Audi Buy Sell 
Audi A6 battery drawing
