Re: '07 Outlook water leaking from lights and driver's side pillar
Had the same issue with our 09 XR that didn't show until last winter when the vehicle was left outside in a couple of snow and rain storms. Finally in July, we noticed the problem developing. Turned out it was a leak in a body seam behind the driver's side tail light. I tore all the seats and carpet out to dry it out. There was some mold developing, but got it cleaned up and dried out. Was a LOT of work. Didn't really notice the build up of water on the floorboard due to we have the fancy molded floor mats. Finally, the battery compartment got so wet and full of water (it's located inside the cabin, passenger side, behind the front passenger seat!) that it caused a driver warning light to come on, and the fix was to clean the corrosion off the battery terminals and half-ass wipe the water off the battery. After the service was performed, I took a look in the battery compartment myself, and found about 2 inches of water still standing around the battery! I tried to find the leak myself, referencing info from this forum, checking for water inside the blower motor cover under the passenger side dash, (it was fine!) and by isolating the front and rear of the car with tarps and a water hose, and deduced it was in the back only, but was unsuccessful at narrowing it to the light, only to the drivers side rear pillar area by the tailgate. (I could see water running down the bottom of the pillar into the spare tire area) No need for sunroof drain tube cleaning or re-routing on this one.
Result: GM repair seam behind tail light $237. And I got to reinstall all the dried carpet, interior trim molding, and seats.
Been fine since. Fortunately, we didn't get any water damage in the driver's side, or in any electronics on the passenger side.
Purchased with only 5,000 miles on it in 09, still driving it, with 86K on her now. Still love the vehicle, best thing I've ever driven as far as style comfort, and utility. Have had other items repaired as well, but for another thread. Running good now.