So I have a 2016 is200t f-sport. Recently I’ve noticed that I’m getting very heavy condensation inside the car in the early morning or during rain events. My Car also now has a persistent musky smell.

I can not find the source of moisture, my seats, carpets and headliner all seem to be dry.

here’s some additional information that might spark some ideas:

1. about 1 month ago my car was in the dealer to have an AC servo motor replaced

2. when this first started I did have some water on my drivers side A pillar. I cleared the sunroof drains as someone here suggested and confirmed the sunroof is draining to beneath the vehicle when I pour water through each of the two drains.

once the drains were cleared I put two large damp rid bags in my car and they’ve each collected a significant amount of moisture but the problem persists.

Any ideas what might be letting this moisture in?

 

I know folks have posted in here where the trunk area (where your spare is) can collect water after heavy rains since some seals may deteriorate over time and can also damage the factory amp. Have you checked there yet? You'd have to pull up the trunk inner liner and remove the spare to see if you notice if there's any standing water. That could be another culprit of the musty/moldy smell you're experiencing.