My ac controls have always worked normally. I noticed the other day that when I put it on floor, it is blowing on floor and defrost. If I select the floor and defrost option it blows a little more on the defrost like it should. So it acts like on the floor setting that something is not opening or closing all the way. I looked under the dash and watched the doors move when I changed the settings. Everything seems to be moving smoothly.

What else can I check?

Mine did that a long time ago and one of the doors on the heater box that controls the vents was not closing all the way. So you might check that out.

You gotta adjust your mode door, check the FSM for the procedure.

If you have auto climate control here is a link on how to adjust the mode doors. Its down at the bottom of the page.
http://www.geocities.com/cbmaxima/maxima/ACC/ACC.html

I have manual controls. Do I stll need to adjust?

I just read the FSM and under the part that says Control Linkage Adj, it just says how to install it, not adjust.

I'd figure installing is somewhat related to adjusting

just says to bolt the bitc# on

Look at the mode doors while someone runs it through all the settings. Thrust me you will see how to adj it.