Anybody know about the plastic sliding plugs found in the bottom door drain holes of the 05 150's ?? Each door has 2 drain holes on the bottom yet one of the holes has a sliding (up and down ) plug that seems to work its way down to block the hole. This was on both the front full size doors and both half doors. Figuring this was a bad thing (blocking a drain hole), I removed all four plugs. Just wondering if anybody knew of a "purpose" for these plugs.

Thanks !!