When cruising in my 2005 DB9, air is forced out the vents when the system is off. The temp **** still controls the air temp coming out of the vents. This is the only car I have owned that does this. Usually, off means off. Is this just a quirk to my gen 1 DB9? Thanks to d.b for reminding me. Curious minds want to know....

 

That and every other Mazda from that era.

 

Off means fan and compressor are off... car still needs air flow into the cabin.
All my cars allow air flow. In thr Vantage, I often drive without the HVAC system 'on' and windows down but still has some warm air generated when it's cool outside

 

Automotive law in the all vehicles must have some type of flow thru ventilation in the cabin to prevent concentration of carbon monoxide. Every manufacturer has done it for the last 50+ years

 

Maybe its just more prevalent in these cars? They do not blow in my M3 or GLA45 when the system is off or they do but not enough to notice.

 

Even though thr cockpit is small, I don't necessarily 'feel' the airflow, just know that the cockpit is warmer than ambient on chilly days with windows down