Brown liquid drips inside cab?

Hey all, I'm new here to the forum. Recently bought a 2002 Tundra AC in nice condition, especially the interior. However, after moving across the country from the mountain west to the northeast, the interior has been finicky.

First off, after some consistent rain for around a week, I found my floor to be wet. Investigated, and sealed off the cowl fastener. It's been dry since.

But, what appears to be mold/mildew has appeared on the passenger side headliner.

Then, I was looking around and found this brown sappy substance in lots of random places. I am taking apart the truck to find culprit, but have had no luck.

It appears one source could be coming from a hole this liner fastener was inserted in. The hole has spongy feel inside, whereas all the other fastener holes from the liner are void.


Any ideas on what this could be and how to fix/solve the problem?
Could it be due to the humid environment? Idk I'm not used to the effects of humidity

Hopefully I didn't post too many pictures, just wanted to show what's going on.

Thanks!!

 

What’s the roof look like? Rear cab light leaking into the headliner? Close everything up and rig up a hose to spray water everywhere and see if you can start to feel it by pressing into the fabric. Better yet you might need to remove the entire headliner and test it that way. Or start to pull up the carpet. You could always buy a moisture meter and go around and start probing areas. Cheap tool to invest in. You definitely have a moisture/mold issue going on big time.

Being in the southeast humidity is a fact of life and you being in the northeast you’re going to get the same weather we get. Mold loves humidity. After a hard rain and that thing is leaking and bakes in the sun for a day you’ll have growth within a day if it’s not aired out. I had a f150 with a leak in the rear window seal that would drip during a rain.