[TRE Cup]

A Long time ago, we met a couple at a Porsche Parade. Their SC was entered in the concours and we got to chatting about their car, how they decided to go to full concours competition.
Well.... they had a funny smell coming out of the fresh air vents , and some small debris of some sort with the fan on. Turns out some small field mice migrated up through the drain tube into the system ! I know, that hole is pretty darn small and the route somewhat circuitous.

Remove the cardboard cover in the trunk, disconnect the cable retainers on the center fan assembly, then unfasten the hard ware / remove the fan. Look inside and see if some critters set up house there. While you have the fan assembly out, check out the fan motor to see if it runs freely and is not the culprit.