#ElectronicAutomaticTemperatureControl

Ryan writes:

Hi Sajeev,

I have a problem with the air conditioning not functioning properly on my ’89 Ford Taurus LX equipped with Electronic Automatic Temperature Control (EATC).

When I start the car on a warm day the AC can blow icy cold air immediately, but the temperature gradually rises to ambient temperature by the time I reach the freeway, and is bad enough that I turn the EATC off. When I turn on the EATC by pressing AUTO, it often feels like it’s blowing maximum heat. I have noticed that when this happens the AC compressor clutch is not cycling on and off. During the winter, the AC compressor clutch clicks on and off. The problem seems to be intermittent and only occurs during warmer months. Also, during startup, you can hear an audible “whirring” noise in the dash, and that started to sound abnormal about the same time the AC stopped working. By “abnormal” I mean it lasts much longer than it used to. I believe the noise I’m hearing is the temperature blend door being moved so the EATC knows the position of the blend door.