2001 Intrips SE Windows Fogging

I have a 2001 2.7L Dodge Intrepid SE (base model w/69K miles) that has been

very reliable and served me well, but I am experiencing a "problem" and 
would appreciate others thoughts.

When the outside temperature is cold (and I will define cold here to mean 
somewhere below 10-15 degrees F), if I try to set the air outlet control
to 
the heater position (even when the car is 100% warmed up), then all of the

windows in the car (this includes the rear window, side windows, and the 
front wid****eld) fog up (and will actually freeze) making visibility 
impossible.  The only solution is to run the defroster 100% of the time
and 
even then, if it is extremely cold (like it is today with the temperature 
f  -6 degrees F on my way into work), then the side windows will still 
freeze up even with the defroster blowing hot air at full force.

I've attempted to clean the windows thoroughly without any change in this 
condition and also tried to look for any possible source for the water 
va****, but also without success.  The engine coolant level is normal and
is 
not leaking.  The coolant temperature gauge goes to the normal/mid-scale 
position when the car warms up (5-10 minutes) and the outlet control and 
blower speed both seem to work properly since air comes out of the 
appropriate outlet dependent on the knob position.  The Air Conditioner
also 
works perfectly and the compressor clutch engages on warmer days when the 
defroster position is selected.

At this point I am at a loss to explain this behavior and would appreciate

knowing if other Intrepid owners experience the same issue or if someone
has 
any idea on what I can look for to see where this moisture comes from.  (I

know some of it comes from breathing, but this has NEVER been a problem
with 
any other vehicles and they generally carry more passengers than I do in 
this car.  Thanks in advance for all thoughts.

        Bob