The vents in my stang will not respond, when i want to change them from blowing on the floor, or the vents, etc. It is stuck in the defrost (default) position, and i can't figure out whats wrong. How many vac cans are under the dash that could be messing me up? I have check the one behind the glove box, its fine, the one on the drivers side behind the gauge cluster, i hooked it up (yellow vac line) and it still does this. The line going accross the back of the engine bay, i found was not connected. I hooked it up, and it doesn't appear to be cracked or anything. Could anybody point me in the right direction? Thanks in advance.. I am pretty damn frusturated with this crap.