'89 reg. cab F150.

Use to have rear window/roof seam line leaks, fixed those a while ago.


But now i'm leaking at the firewall.


Passenger side, directly from under the dash, about 5" away from the kick panel.


What can be leaking water up there?


It only drips there when it rains really hard?


(windshield is new from 2 years ago, and very well installed and sealed, so I don't "think" that's it)