Rain Water Leaks into Cab

[SEA-HAWKS]

So with my issue it was because their was a tiny hole in the gasket which surrounds the window. I took the cowl apart cleaned everything out including the vents along the the sides by where your feet are. My issue was resolved again by replacing the windshield gasket.

To keep debris out of your cowl LMC sells metal meshing that goes under the cowl which I put in and would highly recommend everyone else out there to do as well. It keeps debris not only out of your vent but you don't want dirt and other stuff collecting down there because it will eventually rot out your truck. I cleaned it out with water my hand and compressed air. It is a very cramped space so you may need a air wand.

As far as the flapper goes I would suspect that is where you get the air from for your heater, vent and air conditioning. I would recommend just replacing it or fixing it.

Hopefully this helps. This site from what I can tell is not super helpful about a lot of things but it isn't worth deactivating either. Best of Luck!