progress update
checked both firewall boots behind the drivers side and passenger side footwells, both were dry.

while beating my head against the wall, I opened the rear doors and water fell out of the right door between the two weather seals. found the carpet nice and wet! pulled the trim and definitely water had been leaking here... might have been the culprit the entire time! drying it out in the garage as I type.. really hoping this clears it up and also hoping the cat doesn't find his way into the x5. Will have to repair the vapor barrier on the door before it rains next.


Recap: by this point I have unclogged the front firewall drains and have unclogged the rear and front sunroof drains and pulled the rear headliner to visually inspect those rear drains... AND sealed the vent in the body panel below the fuse box in the trunk as that was also leaking when hosed down. surprisingly the rear tail light gaskets were not leaking at all. I pulled all the wiring harnesses below the microfilter and the same errors were still persisting although a myriad of others since I had pulled the DME connectors and the IPM plugs.

wantonMH: check your carpet in the rear by the door sills the next time it rains or better yet hose down the windows and you should be able to see relatively quickly...!

BF