wrote:

> I have a 1998 Dodge Grand Caravan. Bought it new. It's been great.
> Last fall I had a problem as I was heading into Florida. The A/C was
> on. At some point the CD started skipping and finally quit. We pulled
> the CD out and noticed a bunch of very cold water on it. Obviously the
> tube that is supposed to evacuate the moisture from the AC unit was
> plugged and backing up under the dash. I stopped at a dealer. They
> determined there was a blockage in the evacuation hose. The AC worked
> perfectly for the rest of the trip (about a week).
>
> Living in Indiana, we seldom use the AC in the winter months, so it
> sat unused until about May first. At that point it did the same thing.
> Again I took it to the dealer. They found a blockage in the hose.
> Again they charged me about $40. Yesterday it did it again. I fail to
> believe there keeps getting something stuck in the hose that quickly.
> I've had it for 6 years and it never did it. Now it's done it three
> times in a row?
>
> Does anyone have any ideas, other than just giving them another $40 to
> tell me there is debris in that hose?
===============

The end of the evaporator drain hose is usually constricted, to prevent
noise from air blowing across it while the car is in motion, but that is
easy to plug up with debris. Look for the drain hose, and if you can
find it and reach it, check it yourself. Possibly what is happening is
that dirt or dust has blocked it, or fungus is growing there. It's a
moist environment, just what they like. I've seen this happen, quite a
bit. On one car we propped open the drain hose with a hollow plastic
tube, to keep it open and draining. There were no complaints about
noise, either, after we did that.

In winter, if you use the defroster, you are probably also using the air
conditioning. The refrigeration system turns on by itself, to take
moisture out of the defrost air before the air is heated. Some vehicles
delay turning on the refrigeration until the engine warms up, or
overrides if the outside temperature is too cold.