Just found a soaking wet carpet on the driver's side of my 2013 F-150. Where do I start looking to figure out where the leak is coming from? Only the bottom of the carpet is wet. The side (next to the console) is not. Thanks for any input!

 

Sunroof drain if you have one.
Windshield.

Door splash shields, behind the door panel.
Make sure the rear isn't wet, could be from the rear as well.

 

Third brake light?

 

Third brake light, Sirius antenna, the roof weather stripping in the channels, front and back glass is where I would start. You can also put the heat on high and roll up all the windows and start squirting some soapy water around and look for bubbles.

 

First, has there been rain that the truck has been exposed to?

 

Had the same problem earlier this year. Channel under driver side door sill filled with water, front driver side carpet wettest due to water sloshing forward under braking. Rear driver side was less wet. Tracked the leak down to a rear window gasket. Sprayed carpet with mold and mildew killer above and below, and dried it out twice before locating and fixing the leak.