I have played with the non-climate and the full ACC systems and found a couple of points may help with diagnosis:
Hot blow: lots of condensation on the windscreen on a cold day. If its cold outside, it's going to be dry air also... take advantage of this and try to replace the cabin air which is going to be comparatively very humid.
Alternatively using a cold - warm mix on recirculation: I am presuming that with the non-climate control system, the crude mixer control allows the similtaneous operation of the compressor and cold air feed with a hot vent mix from the heater core. On recirculation, the cabin air complete with moisture content in part passes over the cooling section and causes the moisture content to condense. Releasing 'dry' air back into the mix. Try pure cold on a cold day - although not a freezing day!
I am assuming that on recirculation, once the cabin temp is very high, selecting a lower temp will activate the cooling system, so the attained high moisture content (warm air carries more moisture) can be stripped over the cooling section.
If as suggested, the problem is that condensate is not being vented, the front windscreen should eventually yield to clear with the effect of warmed glass, but throughout the rest of the car, very steamy windows will develop quickly.
On a long hot journey, the cold recirculation is so good, I believe it could be detrimental to driver concentration, please be careful out there!
These patterns have been observed and used with good results, but are not guaranteed to be generally effective.