Until today I never noticed an air vent(?) on the seat back next to the rear drivers side seat. While driving home tonight for the first time ever I noticed it blowing loud making me think the window was open (it wasn't). The climate control was at fan speed #2, then reduced to #1.

Is this an air vent and why have I never heard it blowing excessively loud until tonight?

 

In the hybrid, this is the air intake for the batter cooling system. Don't block it!

 

Thanks Colin. This is why I love these forums, I could not find anything about it in the driver's manual.

 

damnit, i got excited thinking I had a head cooler/warmer in my car that I never noticed.