Strange Wetness

[Dan DiBiase]

I have a strange wetness problem with my A4. The driver's side rear seat 
seatbelt is soaked when I pull it out of the reel. It is only the
portion that resides in the reel when not in use, and it was very wet when I 
checked it this am.

I first noticed the issue about 2 months ago, after I had been driving the car 
in the rain. I assumed it was coming from underneath (i.e.,
the wheel well) but could not see any cracks or anything when I raised the car 
up. I haven't driven the car since Tuesday, when it was dry.
We did have heavy downpours last night and this morning. There is no other 
wetness in the car or trunk. The headliner is dry, the rear
shelf is dry, the seatbelt on the other side is dry. The windows and sunroof 
were closed. Any ideas?

 Dan D
'04 A4 1.8Tq MT-6
Central NJ USA