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Fogging winshield

In wet and especially in wet and chilly weather, my 2000 Toyota Avalon’s windshield fogs up in minutes. When I turn on the front windshield defrost blower, the whole systen blows cold, cold air. So we have to keep turning it on and of and on and off. My wife has a 2001 Avalon with no such problems. I have a theory; a few years ago I got in my car after a big rainstorm and when I stepped on the gas and started to move forward about a gallon or more of water sloshed down on the front seats. It had pooled in the rims around the sun roof. It turns out there is a drain system to take that water down and empty under the car and it was blocked, probably with leaf debris. My mechanic got it cleared out and that has never happened again. But could there be a partial blockage that is leading to this moisture buildup? But even so, how does that explain the cold. cold air coming out of the defrost? I posed the question to Click and Clack but either they didn’t find it interesting or didn’t know the answer. Anybody got an ideas?

When the defrost cycle is selected the AC system comes on as the AC is a de-humidifier. The air should be warm after a short while. Make sure you set the heat on high… don’t leave it on cool as it will make the problem worse.

Missileman, is right. However, you will probably get several contrary posts.