Hey - Thank you everyone for all the replies and great information! Today I worked all day, so wasn't able to try all the tips you guys posted, but I'm going to try working on it tomorrow morning. I also set up an appointment with a GMC dealership on Tuesday, so if I don't get it figured out before then, at least hopefully the dealership can. They said it'd be around 100 dollars for the diagnosis and determine what's going on. Hopefully I can figure it out before then though. Thanks Again, and I'll keep everyone updated!

 

just remember,you can diagnose a water leak as well as a bozo at the dealer.
man,get inside and get a kid to spray with a garden hose, unless you just like tossing $100 bills around

 

My money is on a clogged sunroof drain.

 

Finally Fixed, and only $88.00 out! I took it into the GMC dealership, and they determined that the door was not lined up properly. The door hinge was a little bent which was making the passenger door a little off set, allowing water to enter. They placed the door on properly, gave my hummer a bath, and I'm completely thrilled now. The dinging door ajar light has quit. I'm just crossing my fingers it stays this way now. Thanks everyone for the help!

 

Great to hear you got it fixed. Glad I'm not a betting man.