Well....tons of wires live down there. That leads to corrosion, loss of connections, fault codes.

The cowl....even if it looks good, water can probably get past it. The best thing to do is not only replace it, but put a shield over the cabin filter box. My cowl looks like crap (I need to replace it) but no water gets in because I epoxied a plastic sheet to the box so that water can't get in there.

A-Pillar is an easy check.

 

I believe I have found my water intrusion area. Of course, me being me, I removed all the seats, pulled the carpet and the plastic channel cover up on the passenger (the wire tunnel was full of water) and made a proper mess of the interior in the process. But, after pulling the battery and dumping a large bottle of water over the sunroof and down the window, I saw this...
Of course, the wire bundle to fuse box under the das is right under it. I’m out of useful daylight for this evening. Time for a pint and some pondering. I will be looking for replacement carpet soon...


The bottom left corner of that important looking box looks to have water running OUT of it...

 

Any update?