I have an 99 Audi A4 (AWD). After I shut it off and remove the key some sort of fan or blower keeps running. When I open the hood it appears to be coming from the front left (as you are facing the car). The only way I can stop it is to remove the battery connector. Everything appears to be working fine. It just keeps running (sounds like a vacum cleaner, and will wear the battery down) Any ideas?