I have had this happen to me before, one of my front windshield pillars is broke so I assumed it was coming in there. I'm interested to hear what ur dealer says

 

I beleive there is another "design flaw" in the h3....the moon roof drain or hardware. Mine started leaking through the onstar mic, so naturally i looked up on my roof and saw one of the moldings cracked so i figured it was that. I took it to the dealer as it was still under warranty, and they said it wasnt the molding(they replaced as well) but they were having issues with some of the parts of the moon roofs and once they replaced with the new design it wont happen again(which it hasnt). they had my car for like 3-4 days while they were waiting for the new parts though. It seemed like a hefty repair that would of been bad if not under warranty.
I think some people are just blowing the drains out with air, but its just gonna keep happening unless they go in there and fix the flaw. Good Luck.
Sorry im a little vague, but since it was under warranty i was like "just fix it and give me my truck back please"

 

I had the same isue with the leaking and gave it no urgency.... until my keyless entry started having issues... then the passenger brake light stayed lit with the keys out. Turns out the leak went down the windshield bar and flooded the BCM. Cost me $750 to replace the module. Dealer says it was clogged sunroof drains.

Here it is a couple of months later and the OnStar is raining again. I'll post with the fix if trhe dealer can stop the rain again...

 

There are a bunch of threads on here telling you how to fix it. There are rubber grommets on the ends of the tubes in front with them"x" patern in it. They clog easy with any debris. The back has a small hole in it with the grommets. Cut or drill out the x and the same for the rear tubes.
It isn't too hard to fix it. But when it leaks it goes on the headliner and depending how you park or drive the water runs and finds its way out in one place or another. One place is onstar Mic. I had the onstar in the mirror and also the back carpet soaked on keep once. Blowing with air isbok bit risk blowing tubes off. I blew water through and could tell when it was clear. I also had a bad gasket on the cup on the rear right drain. I had to take it off the track to find it and sealed it up and screwed it back and no leaks since.

As for The dealer upgrade i believe they just put bigger tubes as well.

 

This is an old thread... Never noticed before because of the yesturday coment. Looking on here coulda saved ya 750 bucks if you had of looked at it as soon as you noticed it.

 

That's helpful...

I did a search and this was the first post I saw and commented. I kept digging and found more recent repair posts and have handed that info over to the dealer to fix for me.

Going in Thursday for this repair, Level, Install Bilstien shocks, and 33" Baja MTZ's.

 

I own an "06 H3..had my right side leak which was fixed..no problems since and just recently the left side leaked including the on-star speaker...My H-3 has a sunroof which I love...but when I purchased it ..something was telling me ...call it a gut feeling that I had that this sunroof would present a problem down the road...I was right.....however, my guy works his magic...he claims that the tubes that lead from the sunroof tray take a right hand turn and debris will get caught up in that area ...he has replaced both sides with new rigid tubing with limited flex which might solve the problem ..at least for a little while