I have had this car since new. Dealer replace control head on A/c heater under warranty for this problem. Unit will change from recirculate to outside air after running for a while, without touching buttons. You then have to push recirc button to get back to max a/c again. It will then run for a while on recirc and after a few minutes it will change back to outside air. It did this for a while under warranty. Lke I said dealer replaced control head once. Am I going to have to replace head again to get this to work w/o switching?

I have had this car since new. Dealer replace control head on A/c heater under warranty for this problem. Unit will change from recirculate to outside air after running for a while, without touching buttons. You then have to push recirc button to get back to max a/c again. It will then run for a while on recirc and after a few minutes it will change back to outside air. It did this for a while under warranty. Lke I said dealer replaced control head once. Am I going to have to replace head again to get this to work w/o switching?

Try this:

http://www.automotiveforums.com/vbulletin/showthread.php?t=324015