Musty smell after rains. 2001 Path

After rains I get a slight musty (sorta wet dog) smell in the car that otherwise isn’t there in dry weather.
If I run the heater there's no increase in smell from any vents, nor if I run A/C. Heat may even reduce it.
All 4 sunroof drains are all perfectly clear.
The cabin air filters were previously replaced & I vacuumed fins with a narrow hose.
Cleaned leaves out of door / fender wells long ago.
Headliner is dry after rain.
Mats are very clean.
No pets travel in this car.

I’m wondering if any of these may be the offender - https://imgur.com/a/1pTQiZ6

*If I ever do need to clean the condenser, does the ‘cooler’ housing in the image un-clip so that the bottom comes off easily for condenser cleaning ?
Iv’e read about foaming cleaners for the evaporator(?) (same thing as a ‘condenser’?). But thought that was just for the Air Conditioning, which in my car doesn’t smell.

The roof drain hose(s) at the rear might be leaking into the cargo area. Check out page BT-54. https://www.nicoclub.com/service-manual ... 1%2Fbt.pdf These hoses, when they get as old as ours, have been known to crack and leak. The front area, where the forward hoses are routed, might be getting damp under the carpet

drag, last thing I want to do is take down a headliner.

I'll fill up a pitcher of hot water, maybe with a tiny bit of vinegar added, and test.

Wonder if I could plug up the end of drain tube, pour in a slurry of fix-a-flat, with car on a specific incline, then vacuum it out before it dries, to coat inner walls of tubing?