In addition to the great information provided by Haro about sunroof drains :
http://www.pontiacbonnevilleclub.com/fo ... =43&t=1688 I thought I would add just a little. My headliner got soaked and stained ( in addition to just plain falling apart due to obscene Florida heat) so I suspected that i had a backed up sunroof drain. I got into the car and started yanking stuff out and ended up with everything except the dash out on the front lawn. I discovered that I had a below carpet leak on the passenger front side ( see the post about hidden puddles), a door seal leak in the back, and one completely blocked sunroof drain. Well after i used Haro's info to dig around in my car and get the passenger side drain tube reconnected, I found that I had two completely blocked sunroof drains. So i dug further.
Pull the front wheel and then pop loose the plastic retainers to remove the sight shield that goes up inside the wheel well. You will see this little black "duckbill" looking thing.
I squeezed mine to open it and it shot a bunch of crap out followed by a ton of water. It was like popping a nasty zit.
This is what came out of it...
So if your sunroof drains are blocked and you cant figure out why..try popping your zits!!
Eww.