I've had this problem for some time. I have had the panel that sits between the windshield and the hood off three times trying to figure out how water gets from that cavity under the panel to a location somewhere behind the dash, after which it of course flows down onto the cab's rug.

I did at one time use silicone caulking on every seam that I could see in that gully apparently to no avail. I've been thinking about spraying a couple cans of the spray sealer we all see advertised on TV... the one that the guy puts a screen door on the bottom of a rowboat, sprays it with that stuff, then demonstrates how the boat floats........

Every rain, I have a wet rug. I started putting the truck under the carport alongside my late wife's car to have it dry out thoroughly and stay that way.
However, today I hand washed the truck, not using excessive water, but once again I have a wet rug. The water can get on both sides of the cab but it is heaviest on the passengers side.

I thought perhaps the water was somehow draining past the windshield but there is no seam there and the glass is sealed thoroughly. I bought the truck new and of course it didn't leak then. What am I overlooking? (Joe)

 

Never mind.... I couldn't wait any longer.