A few months back, our 89 5.0 stopped directing the air into the vents. It stays in the default position of defroster/floor. All of the A/C vacuum lines are connected under the hood. My fear is that the problem is with the vacuum canister or whatever it is that it is called. I know that it is in the passenger side fender. I dont think that any of my lines are busted because the cruise control still works sometimes. My guess is that it takes more vacuum to direct the A/C door than it does to run the cruise control. This to me would make sense on as to how the cruise control works sometimes but the A/C door never moves. Maybe at certain points, there is just enough vacuum for the cruise control to work but never enough for the A/C door. If I do have to change out the vacuum canister, how would I go about doing it and where do you guys suggest I go to try and find another one? Thanks.

 

vac referenced comes directly from the distribution block on the fire wall. make sure the line that runs along the firewall and into the a/c area isnt broken or cracked. If it is intact, you will need to remove the glove box and inspect the line where it runs inside the cabin. also verify that its still connected to the backside of the control panel