So my 2000 1500 has had a leak for a while when it rains and it gets the cornor of the head liner wet right where it goes to the plastic trim on the pillar and it runs down the trim piece and gets in my floor board and I have tried a new windshield and pulled the door gasket off and siliconed where it goes to the body and it still leaks
​​​​​

 

do you have a sunroof?

 

No I don't have one

 

Try putting your blower on full (you have to block the cabin vent), closing the doors, and spraying soap water around your windows and doors.

 

This might be of help:

http://www.silveradosierra.com/inter...t25786-20.html