One day during heavy rain down-pour, water entered the interior through the ON STAR ceiling microphone. It stopped for about 9 months and next I notice a very foul moldy mildew odor coming from the front console area(later found it to be the entire passenger floor board). The sunroof drains had been clogged, allowing rain water to back up and run down inside the cowling posts and settle underneath the right carpet and liner. I had found out that the drains get blocked by leaves, grass debris ect... These items cause drainage issues if not detected will lead to mold and premature floor corrosion /rusting underneath your car's carpet liner and carpet. Experts suggest running weed-eater string or heavy gauge electrical wire down the drain ducts (located front-sides and rear-sides of some vehicle). What worked for me was going to a local auto supplier and obtaining an after-market speedometer cable from the "HELP" section of the store. I pulled the cable out of the housing and attached it to my drill. Pour about a teaspoon of fresh water near the hole to see if it has cleared the blockage. Snake the speedometer cable slowly spinning the drill until it stops, slowly increase the speed of the drill until cable feeds forward. Water should start to appear underneath your vehicle on the ground where it should be in the first place. Some say use compressed air and a nozzle. !!! WARNING !!! Unregulated air pressure will cause the drains to pop off of the drain tubes and the entire head liner has to be removed from the car ceiling to access these to repair. The Snake method is the easiest, fastest, and safest way to perform this repair.