Air Conditioner

I have a 2001 Ford Taurus SEL with 86,000 miles. Two months ago, the dealer replaced the A/C compressor and accumulator. Shortly after that, I was driving on the freeway with the A/C on. I had been driving approxitmatly one hour when I tried to increase the air coming out of the vents. As I pushed in the button to increase the flow, I could hear the fan speed up, but the air flow was not increasing, even though the fan was on maximum. I turned off the A/C, waited a couple of minutes, then turned on just the fan. The air flow gradually increased. I then turned on the A/C, which worked fine then. Later on that night as I was driving home, it did the same thing. When I took the car to the dealer, they said they could find nothing wrong. Any ideas as to what the problem is?

It sounds like your evaporator is freezing (icing) over. Do you live in a humid area?
The two ways to avoid this are (1) use a higher fan setting, and (2) set the air inlet control to recycle instead of fresh. (On some cars, the “MAX AC” setting accomplishes the latter.)

I agree, sounds like a frozen evaporator.

There is a sensor on the evaporator that is supposed to prevent ice formation by turning off the compressor if ice forms. It might be disconnected…

It is on the MAX AC setting when this happens.

I will check to see if the sensor is disconnected, thanks.

I live in Virginia, so it is humid.

One other possibility is that the airflow did increase - but just increased from someplace else (such as out of the defrost rather than the panel). The flow of air to the vents is controlled by little doors in the duct work. Those doors are probably controlled by vacuum and the vacuum is created by the engine. If you have a problem with the vacuum lines under the dash the door control might get a little wacky partly depending on what the engine is doing. The next time it happens start feeling around to the other outlets such as the defrost or the floor vents to see if the airflow is there.