2003 S-10 A/C-Heating Air Flow Vent Problem

Have 2003 S-10 ext cab that I bought last week.
I have discovered a problem with the A/C-Heater-Venting system and need help with it. It appears that the floor vents which you would normally use with the heater are stuck open to outside "fresh air" air flow. When driving along, the "breeze" of the outside air is blowing through the floor vents and there is no way to shut it off with climate controls.
Can anyone tell me how to gain access and manually shut the flow off?

Is it automatic or regular AC controls.
Does everything else work ok on it?
If you bought it from a dealer or use car place i would see if they would help on the fix.

Is it automatic or regular AC controls.
Does everything else work ok on it?
If you bought it from a dealer or use car place i would see if they would help on the fix.

AT, manual controls. Everything else works ok. Bought from private party.

Manual controls Off should stop the flow but look behind the glove box (empty and then pull left edge in to swing out and down) and you can see the ouside/recirc door sithat slides to select the intake - check vac lines.

If auto control with temps marked then only way to shut off air is push recirc button on lower left - got both types and that auto one even in Off positions on dials still flows outside air untill recirc button pushed.

Manual controls Off should stop the flow but look behind the glove box (empty and then pull left edge in to swing out and down) and you can see the ouside/recirc door sithat slides to select the intake - check vac lines.

If auto control with temps marked then only way to shut off air is push recirc button on lower left - got both types and that auto one even in Off positions on dials still flows outside air untill recirc button pushed.

Hi,

I checked there, and the moving recirculate/not recirculate door is operating normally. Also, the other vacuum hose I found there is also working-the one that controls the outside air flow to the TOP VENTS. When I pull it off, there is suction and outside air flows through those upper vents and when I put it back on, the outside air flow stops to the upper vents.

The initial problem remains, however. There is still outside air flow to the LOWER (floor) vents that would only normally be used for the heater. I also noticed that heated and a/c air is leaking out of those lower vents as well (small only).

What controls those lower (floor) vents? Is there a vacuum hose down there somewhere? Or a flap? How to access? Can those vents somehow be manually closed? Either that or what controls whether fresh outside air from entering the system at all and can it be turned off or manually closed?.

Make sure you have good full vacuum to heater control.

Make sure you have good full vacuum to heater control.
Where exactly would I find the heater control?

The ac/heater control is right behind the levers and knobs and buttons you push and turn and slide.
The vacuum from engine or intake may run threw a big vacuum ball/can and then back threw dash to the heater control.
Check for good full vacuum from engine to the heater control.
Weak or leaking vacuum lines will not work all of the heater vacuum doors right.