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Moisture problem?

I have a 2004 Grand Prix and have a mystery moisture problem. It is hot and dry in Indiana and while driving from Chicago to St Louis my Grand Prix developed a tremendous amount of water? on the floor of the passenger side. The towel I put on the floor in the back to soak it up contained over a pint of soaked up water and the front floor had about 1/2 of that. All systems seem to be working fine, all fluid levels seem fine, and the AC seems to work fine. The carpet on the front floor going up to the glovebox is dry so the leak is not coming from there apparently. My question is ;“Where in the world is this moisture coming from???” Any ideas out there??? No, I did not have a cooler leaking or any bottles that were leaking or any other obvious causes like that!

A/c condensation in the ducting or a plugged drain line?

Well, the basic problem is that you own a GM product. You’ll have little problems like this as long as you own the car and it will nickle and dime you to death. But yes, I agree that it is condensation build up that isn’t allowed to drain. You may have also noticed that there wasn’t any water on the ground just behind the passenger, front tire. Have an honest mechanic clean out the drain before you get a mildew problem that will be very hard to get rid of. And seriously, even if you have to take a loss, get rid of your GM product. Years of poor management, specifically in worker benefits and retirement benefits, is catching up to GM. If you don’t beleive me just listen to the news: from time to time you will hear something about GM and employee benefits and then all of a sudden the issue is dropped from the media. You can’t be a gulliable liberal about this - you have to read between the lines and listen to what the modern media isn’t saying.

I agree with the clogged drain. What you expained is almost textbook. It may dry and arid where you are, but the ac evaporator does allow moisture present in the cabin to condense and drain out of the tube. It doesn’t matter what kind of car you have, Gm, Ford, or Yugo, a clogged drain is a clogged drain. Another thing to look at is under the hood along the cowl. If you have a lot of tree material or other plant matter will make it down inside the evap box and plug the passage to the drain. Usually taking something like thin wire and carefully inserting into the tube, will instantly let you know if that is the problem. It will drain in a hurry. If that doesn’t work, pull the carpet back from the front wall on the passenger side to see if the hose is actually attached to the box. This is another issue, especially of a mechanic uses compressed air to unclog a drain hose. Good luck!

That is A/C condensation draining into the car because the drain is plugged. It is not uncommon. In most cars it is not difficult to find the drain under the car in front of where the front passenger puts their feet. It can usually be cleaned out using a little compressed air or some string trimmer line. Don’t get overly enthusiastic because you can cause damage. If you are not sure have the shop do it for you.