I have a 2004 Malibu which i just brough for my daughter(her first car) with 3500 miles on it ... not a typo 3500 miles. It was owned by a woman that did not use it very much. Everything works fine but you get air only from the defogger vents. Ac and heat works fine. I looked for a disconnected vacuum hose but had no luck finding it. i'm not even sure if this ever worked. I have a repair book for this year car but there is no info on the vents or any diagram for the vacuum hoses ...

Am i heading in the right direction, that this is controlled by vacuum? .... I tried tracing from the intake manafold but could not find anything, maybe i need to look a lot better or something is missing. Help!