I found a lot of water under the rear passenger carpet and went looking for the leak. I found this forum - awesome by the way - and of course came across all the posts and info about plugged sunroof drain tubes and water coming in thru the onstar mic etc. Because the water was in the rear passenger compartment of my truck and the carpet under the front was dry I didn't think the drain tubes were the cause. Well, to make a long story short, there are rear drain tubes as well. They are located at the end of the channel that the sunroof sits in and they drain into the rear wheel wells. To access them you have to pull down the head liner in the cargo area from the back. My driveway is on an angle so when I'm parked, the rear of the truck is lower than the front and when it rains the water leaks in thru the sunroof and runs to the back of the channel. I cleaned out all the front and rear drains and will be replacing the sunroof weatherstripping shortly. Hopefully that's the end of it!

 

So the tubes got glogged? Or cracks in the tubes?

 

I'm going through the same thing right now. I drilled out the front tube grommets and flossed the tubes with a knotted weed whacker cord... They're perfectly clear and drain fine. Now I'm getting a ton of water on the rear passenger floor.

Can you (or anybody) provide a little more info on how to get to these things? Where exactly are the grommets?

Also, when I open my sunroof, it extends out over the rear tray when fully open, right? Were you able to get something back in the hole to "floss" it once you'd drilled out the grommets?

Thanks so much for anybody who has some clarifications on this second mod.

 

06 hummer.
We removed the interior black plastic housing on each side in the back. Take a knife and cut the end of the hose so it will drain. Poor water in track and allow to drain till running clear and free.
There are some great write ups out on the web. I originally found a YouTube video that helped us.

Chris

 

Here you go.
Chris

 

Chris

 

Happy Hummer,
Thanks for the videos, but those are both for the front - which I've already done. This thread is about the rear.

 

Yep. The rears are located behind the plastic housing in rear. I placed the videos to help future forum members. There are always lots of people seeking info.
I made sure to state the solution 1st.
It is time consuming but can be done. My girlfriend and I did em in a afternoon.
Chris

 

Hummer X Forum • View topic - H3 Sunroof Drain Tubes

Chris

 

I've attatched a few photos of where the rear drain tubes connect to the grommets. As you can see the shape of the grommet where the water exits is very small so I just took an exacto knife and trimmed them so the opening is larger. In the photos the black tubes with white tape on them are the drain tubes and the grommet is in the pillar just behind the seatbelt thingy - unlike the front, they are very easy to access once you remove the pillar trim. To access the drain tubes at the end of the sunroof channel in the ceiling you have to first remove the rear side window trim, remove the rear seat overhead handles then go to the back and pull down the ceiling trim. You will then be able to access the rear sunroof drain tubes. I had pulled out all the seats/trim/carpet while trying to find the leak - you won't have to go to that extent in order to get to the drain tubes. Good luck!