I have attached a TSB on a similar problem with these vehicles. You must have a leak that is allowing the water to enter the AC Vent system.
Review this TSB and look in the same area............
Hope you had a great Christmas!
Air Inlet - Heater Blower Inoperative/Interior Floor Wet
File In Section: 08 Body and Accessories
Bulletin No.: 01-08-57-003
Date: September, 2001
Heater Blower Inoperative or Water on Passenger Floor
(Install Sealing Strip)
1999-2001 Oldsmobile Alero
1999-2001 Pontiac Grand Am
Some customers may comment that water drips on the front passenger floor or that the heater blower is inoperative in cold weather.
This condition may be caused by water entering the fresh air inlet to the HVAC case due to poor sealing of the air inlet screen to the fresh air inlet opening.
1. Open the hood and remove the windshield wiper arms.
2. Remove the air inlet screen panel and replace the foam seal. Refer to illustration above.
3. Inspect the cowl drain holes located at each end of the cowl. They should be open and free of debris.
4. Reinstall the air inlet screen.
5. Make sure the lip on the lower windshield lace sits on top of the air inlet screen panel when installing the air inlet screen.
6. Reinstall the windshield wiper arms.
Thursday, December 25th, 2008 AT 11:46 PM