Inside of drivers door wet and smelling musty

[Nalby]

My truck has been in the driveway for a couple of days and it has been raining. I wanted to do a little maintenance on the truck so moved it into the garage. When entering the truck it smelled a little musty so the investigation began. I removed the drivers door panel, looked inside, it was quite wet and the smell much stronger. The door was completely closed and the window up. Any suggestions where the water is entering the door?

[2016 Sierra Owner]

The outside of the window is not sealed off very well. Water will leak into the door and drain out the hole in the bottom of the door. Usually it will drain out when you 1st open the door after a hard rain. It sounds like the drain hole on your door is plugged. My current and previous GM (14 and 16) trucks would drain water from a point under the door radio speaker with the door open.

[DaveHC]

check your rear window, they leak like sives on these trucks, search in this forum, over 150 pages of stories, mine leaked so bad i found out when i started up a hill and heard water moving, all carpets soaked front and rear. check your carpets