If your auxillary fan is not functioning you will still get cold air when the car is moving. If you have no cold air at all most likely you compressor is not running. with the AC on, open the hood and see if the compressor clutch is engaging and the auxillary fan is spinning. The most common reason for no AC is low freon or electrical like fuse or relay.

__________________
2013 X5 3.5i M Sport
2004 M3 cabriolet SMG