21 1500 Silverado - air through vents when off

[Josh42089]

I have a 21 Silverado with the single zone climate controls. Manual. I had the ac on through the front vents. Shut it off the blower and opened the windows. I noticed I could still feel cold air coming out of the vents.  Not blowing but still cold like it wasnt shut all the way or something. Anyone else’s like that? 

[Vigilante375]

Yes, mine does this and so does my ZL1 plus the rental's I drive from time to time for work.  Something that newer vehicles have been doing.

 

It'll be hot or cold or whatever the outside temp is.

[Josh42089]

7 minutes ago, Vigilante375 said:

Yes, mine does this and so does my ZL1 plus the rental's I drive from time to time for work.  Something that newer vehicles have been doing.

 

It'll be hot or cold or whatever the outside temp is.

Well this wasn’t outside temp air. It was 80+ outside and I was getting ac cold air from the vents. Same in the winter time with hot air. 

[jwhjr]

I'm guessing it's just blowing the rest of the cool air through before it gets to the outside air.  Usually takes about 5 min depending on how warm it is outside before it starts getting warmer.  I've noticed that on mine.

[newdude]

Normal.  Keeps positive pressure in the cabin.  When you turn it off, the recirc door opens up to let air flow into the cabin and keep the cabin pressure vents working.  

[Salsa De Piña]

Newer cars have been keeping the blower on for a bit after the AC was running to dry the evaporator and prevent mold from growing.  Not sure about GM trucks specifically, but many cars do this nowadays.

[gmtech2014]

This is normal. GM calls it Afterblow. There are a few parameters that have to be met, but the jist of it is that the truck will keep the blower motor on for a set period of time after the truck as been shut off to dry off the evaporator core.

[Josh42089]

Thanks for the reply’s