...played with. No vaccume leaks? The fan blows, but it just blows cold air. I have checked vaccume lines, and they are all on tight. I don't here or feel any leaks. I'm not sure what they do when it is not working. As soon as I start fiddling with the hot cold switch and the vaccume lines, it starts working. I worked on another one that was doing somthing similar, and It got sent to our other shop and had a body control module put on it. I work for a school district, and only one of our shops has a computer to program the module. Our head mechanic did the the work, but he has quit. Does it sound like it could be the same thing, or somthing differernt.