Auxiliary Fan
WARNING: This page does not describe the selected car, but rather 33 other vehicles, including the 2010 BMW M5, 2009 BMW M5, 2008 BMW M5, 2008 BMW 760Li, and 2007 BMW M5. However, it is still accessible from the selected car via links, so may be relevant.
The auxiliary fan is standard on all vehicles with IHKA. Besides the engine cooling, the auxiliary fan is also needed for cooling the condensers.