Ditto...as stated every time this question is asked...the IHKA's fan will run as soon as a call is made on the P-bus (when something activates the general module, door modules, remote key)...as this sends the WAKE signal...and begins to prepare the vehicle to be boarded.
It should run until the vehicle goes to SLEEP...which should occur 16 minutes after no calls are made (see what wakes up the vehicle in paragraph above) after the vehicle has been shut down.
If a call is made before the 16 minutes , then the little fan will turn back on.