so, new member here and im doing a little investigative air conditioning problem solving - I think ac related anyway..... wife has an 2016 Audi A6 sedan than in the last couple of months has developed a musty dirty laundry like smell. I can't find any wet damp areas in the car, the ac condensate drain works as do the sunroof drains. in trying to figure out the problem we've brought it back under warranty to the dealer and was told it is not a warranty issue and its normal for this area, etc.. They already detailed the car at our cost and now want to deep clean deionize it. I say, solve the issue and stop trying to just cover up the smell as it keeps coming back. Anyhow, in trying to figure this out ive come across some articles that say to only run the ac in recirc mode and others that suggest only run in recirc for a short period as its good to let fresh air in. Anyhow ive noticed, my new TLC is the 1st car ive ever owned that is set to defaiult recirc mode for the ac - and stays there. any thought as to what the smell might be is appreciated...... thoughts as to why the ac default in the Land Cruiser is recirc mode thoughts on does it make a difference - recirc or not??? thanks and I hope I have the right form.