Hello guys I do need your help.

I have an Audi A4 1.8 turbo 2001 model.
Two days ago, The symptom started with very high speed fan sound coming from passenger side I thought it was a normal thing to be on. so I didn't care much. I came out to my car with a dead battery and i thought that I did turn on one of the lights over the night so I jumped the car and drove to work, came out to leave and the battery was dead again and jumped it both times.
Today morning the battery was dead again and tried to jump the car but didn't start at all.

I suppose that the fan stays on full speed over night which drains the battery power

I don't know what to call the fan which is located passenger side (under the air filter).

if you know about the problem please let me know

Thank you very much.