Cab retaining water, common problem areas?

[baglie1]

I have a 2012 GMC Sierra 1500 Crew Cab 4WD and a few severe storms recently passed through with very heavy rainfall and winds. Now, when I drive, I heard fluid/water sloshing around!!! The bed is dry :-(. Are the 3rd Brake Lights an issue with these trucks? I've only had the vehicle for a few months and have barely driven, so I'm still not that familiar lol. In my mind the obvious are the rear windshield and the 3rd brake light gasket...

[richard wysong]

You are probably hearing water in the doors, make sure the drain holes are clear

[nitrozamboni]

It’s probably water in the doors. Mine had tape over the drain holes! Poked them open and that took care of it. Now I’m waiting for the rust to come through!

[Z45]

Dirt settles in the door drain holes and traps water....lower corners of inside door skin.