I have a 2007 LT Tahoe that has a constant drip of water from the rear passenger door. I think the cause of this is a broken exterior window sill or trim. Not the rubber sweeps but the plastic outer trim. It runs along the side of the window and up the rear pillar about 6". Im missing about 3" off this trim from the top of the rear pillar. I think this is where the water is coming in. Does anyone know where I can order a replacement for this trim or sill. I looked around online but no luck so far. Im trying to avoid the dealer! Thanks!

 

GM parts direct http://www.gmpartsdirect.com/ is a good place to start
1aauto.com has seals but probably not for the 07 yet

 

Since the early build of the NBS had a lot of the "hockey stick" trim come completely off and no one complained about any leaks, I doubt that it's your problem but you'll find out after you replace it.

 

I have the same problem. Right rear door. i came outside a few times and found water on my running board and could not figure out where it was coming from until I opened the right rear door and heard it sloshing around in there. I simply sat there in a chair and held the rubber strip on he botom of the door away from the door until it drained completely. my Hoe is still under warranty. Next time it happens, straight to the dealer. This is a good way for the door to rust out and I'm not having that happen to me.