I wanted to post this in the hope it will help others who have ATC problems.
I finally took my 2000 limited to another dealer (Mercury) and convinced them that I did have a problem, something my selling dealer refused to acknowledge.
picked it up today and works great, although I haven't yet tested it thoroughly. but I can already tell the difference. previously, if set below 80 degrees, it would blow cool/cold air. it now seems to work as it should, blowing warm air (even at 70-72 degrees) and increasing/decreasing fan when needed. my feet no longer get cold. outside temp today is about
the only problem found; the 'car temp sensor assy', about for the part. labor, of course, was additional. in addition, the service dealer said there was some lint blocking the sensor, so you might check this. I do not know where the sensor is located in the car. since I have had this problem for several years, I feel sure the sensor was originally bad. it was NOT the blend door.
needless to say, the place I purchased my car will not have a repeat customer. I live in dallas-ft worth area.