In my burb ('87 w/ AC) I get the majority of the air blowing right out the front vents even when I the selector is on "Heat" or "Defrost". The good news is that when I switch from the two, one shuts off and the other opens up, but the vents are always blowing. This leads me to think that the vaccum tubes are working properly, and that the damper mechanism is messed up and/or jammed. Since my heater only blows hot when my foot is on the gas I'll be in there replacing the heater core tonight (I already replaced the t-stat). Any ideas on this before I go tearing into it? Also, it has rear heat, but the PO removed the core for it. I'll be replacing that while I'm at it. Any watch outs there? Thanks.