Chrysler Repair: 98 van leaks water into the front passenger area, similar to rain, air intake system

Question
My wife and I bought this mini-van in May used. We noticed that whenever it rains outside, the mini-van takes on water. We don't actually hear it during the rain but afterward, when we start moving, we hear water pouring in for a few moments from behind the glove compartment and the carpet on the passenger side below the dash always gets soaked. In heavier rains, we can hear the blower fan tread water for a few moments too. Where should I look for the source of my problem... below the dash or from under the hood?

Answer
Hi Kevin,
My inclination would be to look at both areas but not specifically those you described. The area in front of the windshield where there is the grille for the air intake is one possibility. You could try putting water in the grille opening (at a rate similar to rain input, don't flood it) and determine whether it is draining out completely by capturing it from under the van where it should drain from the air intake plenum completely in the same amount, rather than entering the air intake system. If the fan gurgles after this test, then you need to remove the grille and clean out debris over the internal drain area. Write me back for how to remove the grille.
The other area would be the windshield glass shield/seal. You could put water on the edge of the windshield (but not on the grille area) and observe for leakage under the dash. There is windshield sealant you can apply to the seal if you can localize the area where it is leaking by trying different areas with the water test, one at a time.
I suspect that the leak is not coming from inside the engine compartment (under the hood) because it should be isolated from the cabin via the metal firewall.
So try those two kinds of tests and write back if you need more help.
Roland