vent controls

need a little help. I have a 2000 Silverado. when i shut the temperature control fan to off, the unit still lets a slight amount of air circulate. In addition, when i turn the A/C off (switch to vent position) and leave the recirc ON, the A/C unit stays ON. when i move the recirc to outside, it goes off. help, please....

It sounds the same as my 04 1500. When you cut the fan off some air still comes in from outside, in fact the faster you go, the faster the air comes in the truck. Most vehicles do this, but they normally make it come out of the vent in the floor, where you do not notice.

As for the recirculate button, I do not see much difference between recirculate and AC+recirculate. They both seem to be just as cold. I rarely turn on the AC because it is cold enough with recirculation on.