GM Suburban HVAC question

[Lason]

OK Im about to replace the heater core in my 2001 suburban that I have been putting off for so long. Anyway I have had another issue that I am going to try to fix but wanted to see if anyone else had this issue and knows what the fix is.

Air blows out the vents even with the a/c off while going down the road. When I come to a stop, it stops. I know there is a leak letting outside air but where?

Rockauto sells a blend door actuator but I dont think thats it. I can select floor, vents and defrost just fine. I can also select heat and A/C fine so I dont think its an actuator as much as maybe a door seal or something.

Any thoughts before I order parts?

[G..]

That's normal for a Chevy. Select the recirc when off if you can. Every Chevy defaults to outside air when off unless you command otherwise

[Lason]

Ill try but the light on the recirculation button goes off when I turn the air off.

[Lason]

Ill be damned, hitting the recirculate button worked! Thanks for the tip, I cant believe Im going to have to do it everytime I start it up though!

**EDIT** Forgot, thanks for the tip!