There is a water management system that sits level with the back of the top where it meets the trunk in that area. What happens is the water rolls off of that area and into these little resevoir "bags" and then drains down tubes out of the car. What was happening with the older model verts (11 & first half of 12) is that the bags were not big enough. Also when they'd drain down they act like a bladder and deflate. When they were empty/deflated they'd pinch or close off the drain tubes so that next time the car was exposed to water it'd fill the bag but have nowhere to drain but out into the car. The redesigned ones are larger and are repositioned so that when they deflate they no longer block/pinch the drain tubes.
This upgrade is not a part of the recall. Our old car was determined to have the issues so they ordered the parts. The actual repairs are taking place now that GM owns the car.
Does this make any sense?
