To recap, discovered the wet carpet as I was replacing the fuse for the indicator that blew this week. The car has the winter floor trays in it, so wet carpet was not noticed before. The car is a 1992 240 wagon that I bought two years ago, it had been a one-owner car and came with the fully stamped record book. Car was in great condition, 155,000 miles then, 177,000 now. Unfortunately I have to park it outside and we have large Douglas firs on the property. Great lumber trees, but awful if you are a homeowner and one who has to park cars outside! Two weeks after getting the car back from my daughter I installed the Volvo hood vent covers on it to stop most of the needles from finding their way into the vents. (My '80 has the cover also, and it does a great job.) Today I pulled up the carpet in the footwell area keeping my fingers crossed that I would not get a nasty shock. The good news is that the floor area is positively pristine, looks like how it probably looked when it came from the factory! I noticed a wet area by the fuse box cover, on taking the cover off saw that water has been coming through there. I have cleaned out all the debris I could find in the engine area, but do not know where specifically to look for the leak source.
Also, once the leak has been located and plugged, would you recommend replacing all the fuses? Having the indicators suddenly non-operational was bad enough, but the fuse to the fuel pump going on the freeway could be really bad.

Thanks for any replies.