I am chasing down a few leaks in my trailer. The current suspect is the clearance lights (I've eliminated nearly everything else). The water leak appears in the trailer along an interior wall seam just forward of the streetside windows, along the hinges of the windows, and along the top edge of the rear (bath) window.
For a long time I thought the windows themselves were leaking along the hinges (and perhaps they are). But I think it's more likely the water is coming in from above, and just appearing when it hits the windows.
So, is there a technique or procedure for absolutely positively sealing clearance lights?