Strange Noise When A/C goes on

I have a 2000 740iL. When I turn on the A/C, I hear a strange noise, I don't know where it comes from because I pop the hood and theres no noise, but when I go back inside the car and the noise is still there, you only hear it when your inside the car with A/C on. What Could This Be???


Thanks,
Luis

whats it sound like? A piece could be loose? blades could be coming apart?

whats it sound like? A piece could be loose? blades could be coming apart?



It sounds like a "Booooooooo" sound it just keeps on going until the A/c is off, it gets annoying in the ear after awhile, but its not too loud, its like coming from under the dash. It must be hard to fix it if its coming from there.

I sounds like either the motor is going, otherwise something is obstructing the air flow, and the moving air could be making what ever is vibrate, creating a hum like an instrument. Contact your local BMW, see what they could do.