filxt

My 2002 tahoe's ac is stuck on outside air. When I push the button for max ac it turns on but it does not switch. I know this because there is not a boost in the amount of air that is being blown and also because I still get alot of the outside odors. Is my swith gone bad? Is it a vaccum leak. One other note, if I switch it back to normal outside air, it will eventually switch by itself to max ac. ?? Any ideas other than having to take it to the dealer for checking?

Thanks for any help


Felix