Hi-
I know lots of us have had the problem of the carpet getting wet after a big rain. My leaks have been bad enough that I've had to remove the carpet etc. to dry them after every rain.  I had done the usual- slicone seal the windshield, the wiper shafts, and the antenna base.  None worked.  Finally 2 weeks ago I removed the antenna checking for the "drip-loop" in the coax cable that comes into the van.  Not there. The cable sloped gently right toward the interior of the van.  This could be it.  I rearranged things so that not only is there now a drip loop, but it extends down through the rubber access plug below the antenna (cut a small hole in the center).  I also noticed that on the bottom of the antenna base there is sort of a drain hole that easily accepts a small piece of hose.  I attached a short length of vinyl hose and ran it out through that access plug also.

Last weekend it rained heavily here for several days.  No leaks, no wet carpet.

Gary