[SSport16]

Originally Posted by NY Andrew

So that's how they designed it? I still want to double check somewhere to make sure this is true (I believe you just for my own knowledge want to see something written in stone). I see what you're saying that's the only thing I could think of but still I don't understand why we can't simply turn it completely off, that's just weird..so the fan is always on and that also means I'll have to replace be cabin air filter when I've only done that once out of all the cars I've owned and that one was because of smoking.

Yeah GM HVAC systems are like this, itnis essentially still pulling air in from outside since the vents are still open. Now with fan systems on newer cars they run so much more than way back when. Even after you hit the power button to turn the system off, it will still pull in outside air, hence if you hit the recirculate button it will close out an any air coming into the the open vents. There is nothing wrong with it. If you think of this way, if you had a fan in front of an open window in your house, then shut the fan off but left the window open, you would still feel air coming in, just obviously not blowing in from a powered fan since it is off. Now if you closed the window, no more air would then come in...that is where the recirculate button comes into play when the system is off, it acts like a vent closer.

All of my GM HVAC systems have 2 buttons, one for recirculate and one to pull air from the outside, it appears and correct me if I am wrong from me sitting in a few 6th gens so far, there is only 1 button for recirculate, so if that button is not pressed then I would assume it pulls fro, the outside.