One thing that annoys me is that as soon as I turn a little heat on in the car, cool air start blowing up from the air vents in the seat. (Yes, I know I could always go to the trouble of separately adjusting the seat temperature every time I change the inside temperature.)

Why does the GS feel it needs to turn the fans on low in the seats just because the heat or A/C has been turned on in the car? Turning off the heat or A/C turns off the cool air blowing from the seats. Granted it's not a lot of cool air, but why any? If I want air from the seats, I can always turn it on.

 

Interesting. Air movement from my vented seats only happens when I actually turn the seat controls on. Does not move air while either the heat or A/C is on.

 

Yeah, only get cool air from our GS seats when we turn them on. IIRC, there are floor vents for the back seats in the GS. Maybe the duct under your driver's seat came loose? Take a look.

 

Either there's something wrong with your car, or with your perceptions. The fans inside the seats -- the ones that you turn on with a dial near the storage console to either heat or cool -- are not at all affected by the car's climate control system. They are completely independent systems.