Fan working, but no air from front' vents

[AEnrico]

Hi, got a strange issue with a 2002 E46 325Ti, when I turn on the fan, it starts and I can very clearly hear its noise, but no matter what air seems to come only from the bottom vents, and maybe the upper (defrosting) ones, but there is no way to get any moving air from the front vents.
Knowing exactly nil about BMW's forced air management system, could someone provide a description of how it works, and some kind of troubleshooting checklist or guide?

THX!

[Critter7r]

Is the thumbwheel set to full "hot"? Are the vents closed?

[MarcoZandrini]

Does the car have the manual climate control or the automatic climate control module (IHKA)? The IHKA contra the vent doors located in the dash. A bad actuator or a broken actuator link rod could be the culprit. Btw, the red dot/blue dot wheel merely controls the temperature of the air flowing out of the vents.

[AEnrico]

Mistery solved! I lend the car to a friend of mine, who had tinkered with A/C control and fans, it seems he regulated the front vents as to not get any bleeding air whatsover. Now I tinkered it back, just do not ask me what i did!

But thanks anyway!