Originally Posted by 03SLE-SteelBlue

here it is late may and i have a new-ish but likely related situation. a few weeks ago with obviously no snow involved there was some condensation on my inside glass, mostly the rear. Same old thing, i thought, but no snow so even more puzzling. i just shrugged it off.

then, about 3 weeks ago i could smell mold or mildew inside. i pulled out the loose carpet pads and the built-in floor-only carpeting was pretty wet in all 4 foot-wells. i thought it must be from accidentally leaving windows open in the rain. i got religious about closing all windows, ran high heat at idle for hours, closed doors, opened doors, etc and after a few days the rear foot-well carpets were dry, the driver'* still damp, but the front passenger'* still very wet. no more smell or i'd have panicked by now.

i started putting kitty litter in that passenger foot-well to soak up the wet. by god, every morning the litter had turned to clay mud and needed sweeping up and new litter put down. the wetness is worst near the seat and next to the center bump, but that could easily just be my driveway. this went on for maybe 10 days til i got sick of it a couple of days ago. no, the windshield isn't leaking down, tested that. someone suggested a rust hole under the car. hmm, maybe, but wouldn't it drain just as fast as it came in?

so just now i went to an auto-body place and the guys best guess is a clogged heater box/core drain. he said it might get un-clogged with a little tweak. me, i know nothing!