hmmm this is Odd I went to test the whole recir and defrost. in my car (I only had used defrost maybe twice before) defrost turned on Recir maybe 4 of 6 times...??? Idk why it isnt always or not at all... sorry that wasnt the problem.
In my experience (Like frank M said) the only way to get condensation inside like you are describing is moisture (ambient) in the car.
since its cold where you are is the air outside dry? if so you could just crack your windows try to get some dry air in and see if that solves it. (like JTP said)
If that doesnt work (which it has worked on my box (1 of the 2 times i ever had to use defrost i cracked the windows to speed it up))
then IDK
