I really don't know how to explain this. I took the switch off the dash that has a bunch of little vacuum hoses connected to it. I followed 2 lines to a thing that switches the cooling from floor to defrost, if I move it by hand, it switches and blows out the defrost vents, but when I just turn the switch on the dash, nothing happens. All the vacuum hoses look fine and have no cracks or anything. What is wrong? I'd like to get some airflow in the truck but as of now it just blows out everywhere behind the dash and not through and vents, all the duct hoses are attached. Any help is appreciated.