I just had to change the tire on our '95C220 and noticed that there is a about a pint of water in the trunk under th carpet in an intentation behind the driver's side tail light. The rest of the trunk is dry. Could this be comming from the tailight? any ideas?

 

I had this problem on a totally different car but it sounds like you wanna whip out your light cluster clean up the sealant rubber and run round it with some silicone mastik [i live in uk and there could be different translation],let it cure for 1/2 an hour and pop it back in this cure your leak.