2006 Prius A/C Temperature Stuck?

When I camp in my prius and have it running overnight the a/c is blowing cold through the center vents
ok. I have the auto off. It's in Florida so it is hot during the day and cold at night right now. Once I set it to
center vents, max blower, max low temp it works fine, until I wake up the next morning and the car is warm with cool but not cold air barely coming out of the center vents as they were originally set. The blower fan is still blowing on max but the air flow seems restricted or blocked somehow.

Its as if the temperature is stuck around 70 for example. I should be able to blow ice cold air fully through the center vents even if it is cold outside.

I cycle through the different modes and blends and toggle the auto several times
to try to unstick it, but it doesn't work.

It seems like both the blend and mode door actuators are working since during
the day when it's hot out I can cycle through the different modes and also can get it to go to heat and back to cold.

Eventually later in the morning as I start driving the cold air finally comes
back and blows strong. Playing with the buttons doesn't seem to have an effect.

Have any of you experienced this? Would like some input before I start pulling stuff apart and throwing
parts at it.

 

That might be a possibility because I noticed that at the bottom of the heater box behind the center console I pulled the floor carpet aside and noticed some droplets of condensation that were frozen. How could I prevent that?

 

Thanks, I leave it on fresh air overnight. The cabin filter is new. I'll check the radiator fans.

 

Thanks, good idea I'll try setting the temp like you said. I cleaned the drain tube last september, I'll check it again.