Do u have ur AC on when this happens? (To defrost windshield)
I have a 02 T/A. Just had to replace the carpet and rear seats. Check the drains. Good Luck
How old is the car? If it is a 3rd gen, the leak might be from your heater core, not the "wiper compartment". See if the liquid smells and feels like antifreeze. If its the core, try a can of "stop leak" before trying to take out the core. It is a tight place to work and not a fun job.
It could also be from the evaporator which is usually in or near the dash...it can be clogged and ice will form on the outside. After u turn off the car the ice will melt...
Looking for a Used Pontiac in your area?
CarGurus has 15,319 nationwide Pontiac listings starting at $595.