Heater Problem

[Camaro_SLP]

When I first bought my car, the heater worked fine. There was a certain point when it improperly functioned, but I ignored it until now...because of this damn cold weather.

No matter which mode I have it in ( blow on the floor, come out the middle vents, blow out by the windshield..etc) all it ever does it blow out through the vents right below the windshield, and the ones by the pedals. No heat, or any air is blown through any of my middle vents. After awhile, the car will warm up just fine..but I'm wondering why I can't get any of the middle vents to blow.

Any suggestions?

[Ian]

same thing happened in my truck, and i was told it was a vaccum line somewhere that either had a leak or split open or came off.

i just dont know where to even start looking for it.