I have a 96 Explorer XLT 5.0 with all the extras. I have since I've
owned it always had the nagging "non adjustment" of the air
temperature by which I solved by zip tieing the hearter control valve
in the summer for cold air and releasing it in the winter for warm
air.  You can imagine my frustration during spring and summer.  But
alas, I have finally read the article about the actuator and it's
problematic break which I believe is my problem as well. I have taken
it off and I am in the process of drilling and glueing as we speak.
But I have always had another minor problem as well and wonder it this
first solution is the answer to my problem or if I actually have two
problems.

Along with the temperature control NEVER working (I'm hoping this
first fix solves that problem), the air flow selector has seemed to
work when it wants to.  Some times it will blow out the vents,
sometimes it will blow out the defrost, sometimes it will blow out the
floor.  The defrost (being the default as I have read) seems to be the
most prevalent.  However, If I get in the car and turn the selector to
max a/c, it will continue to blow out the defroster.  But I can shut
off the car and come back to it some time later and miraculously, it's
blowing out the front vents as they should.  Now if at this point I
turn the selector to say defrost, it will, but if I immediately turn
it to max a/c again, it would stay blowing out the defrost vents.  On
occasion, if I turn it to just 'vent', it would act like it should and
blow out the front vents with not a/c, but I could go straight from
'vent' to max a/c and the a/c would come on but the air would redirect
to the defrost vents.  Believe me, it's gotten me confused too.

Now I'm thinking if the blend door fix does not correct this problem
(perhaps the flow is based on the temperature blend door mechanism?)
do I have a vacuum motor issue?  Is that even part of the air system?
And if so, where exactly is it?  I have seen the vacuum lines coming
off of the selector dial, but they disappear into the dash where I can
trace then without taking the dash apart.

One final note, the heater control valve (under the hood, next to the
evaporator coil) has never worked on its own no matter where the
selector was positioned.  I under stand this will be opened and closed
according to certain positions on the selector knob.

I still have the actuator out and would like to try and get this
solved before I put everything back together.  So any suggestions
would be greatly appreciated.  I know I have exausted my resources and
haven't found this particular problem addressed.  Thanks again in
advance.