I was now told that the knob got tight at one time, and now it kinda "free wheels...almost like it's not doing anything".
Does that typically point to the white gear at the bottom, or a damaged control lever/control assembly up top (which I found a TSB for also)?
MPE:
Are these the parts I'm looking for and does this photo show anything removed, or do you just peek up there without removing anything? Seems this guy had the gear issue:
http://www.nissanclub.com/forums/2002-2006-nissan-altima-discussion-2-5-3-5/281108-heater-sucks-3.html
Thanks again for everyone's input. Hopefully I can make her happy with AC on Friday :).