https://www.wholesalegmpartsonline.com/showAssembly.aspx?ukey_assembly=432983&ukey_produc t=2480825

Part #2. Is this the door that is supposed to block outside air when the controls are in the Off position?
There is air coming in and the amount is increased depending on vehicle speed.
I can change the temp of the air from that respective ****.
It's annoying enough that I'd like it fixed. Pig farms, stinky diesels, death smell from zombie apocalypse, not good.

I've been looking for exploded views of the system but the above link is where I'm at for now.

 

There is a small flow of air designed into the system, to have a positive air flow so that any carbon monoxide will vent out. And yes, it is temperature controlled.

 

When I want to keep out dust or smells, I turn on MAX AC. That recirculates air inside the cabin and stops outside air from coming in. It does do the trick.

 

Cool. Thanks for the replies. The amount of airflow seems a bit obnoxious. Driving at highway speeds is almost letting as much air in as when the fan is on low speed, if that takes sense.
This van is new to me so I'm still getting used to it. Today I was cycling through the various settings while parked in the driveway with the engine running.
I was able to tell that Max AC does recirculate or at least sounds like it. Not quite sure if it's 100% but nonetheless.
Other vehicles I've owned without a separate recirc switch would state that outside air is blocked when on Max AC or Off.
I'll keep digging around.

 

Of course it does. I don't think there is any kind of door at the air inlet. There is nothing to stop wind or forced air (other than the body of the vehicle itself). I simply shut the louvers on the vents that I don't want air from. Some will still leak through the floor ducts and possible the windshield defog, so I adjust the temperature to suit me. Usually a bit fresh air is welcome anyway.

 

Off should be Off. Plain and simple. I can open a window if I need a dose of air.
There are many times and situations when outside air should Not be entering the cabin.

 

As was mentioned, it's probably intentional. Carbon Monoxide is undetectable to humans.

 

Dunno how accurate this is but the recirculation door is where I'll look first. I might be able to look in the duct housing if I remove the blower motor.
I gotta know what's what. Its just my hang up.

 

Both my 93 & 05 Subs do this - as stated above it is a safety fresh air inlet to keep you alive & alert while driving.

 

Humans breathe out CO2 not CO. The CO would be from the stinky diesel that I'm stuck behind that GM has entering the cabin on my behalf?
It's wrong to not be able to secure oneself from subjective atmospheric conditions for a time until said conditions are removed. wtf?
I'm all for designed comfort but it'd be nice to shut it off once in a while when needed.

I'll play around with it. Maybe I'll duct tape the inlet at the base of the windshield and drive at speed(s) to determine if there is another intlet.
I've done some reading on truck forums and their panties are all up in a bunch also. One guy found out that the recirc door was warped.
Another found out that GM has the door at a 90/10 percent of closure to allow the outside air to enter. It's either a design element or a design flaw.

No worries. This is my first Chevrolet. I'll either get used to it or get rid of it.