SPAZZ,
If the blower is blowing at all I would say your problem is either vacuum or the actual lever arms that open and close the different venting routes under the dash (from floor to dash..etc). The resistor is one of those, it works or it don't parts, no gradually going bad. I had a simular problem some time ago where a little air always blew from the floor area and the dash vents seemed to be on half speed. After searching high and low I found I caused the problem when I installed a siren. One of the siren wires was caught in the floor venting door under the dash so it couldn't close completely. After moving the wire she sealed up tight as a drum. If you have mods and have routed wires under the dash it might be worth looking into. Just an idea...carlymac