AC Not cooling at lower fan speeds

[aph_tjk]

Hi!

I have a 2003 E with 192,000miles. Already replaced both fan motors last year when the AC wasn't cooling at idle (thanks to the resolutions posted on this Forum). No other AC work done since I purchased it at 40,000miles. All belts were replaced last year as well.

In SW Florida, so AC is a must, even in the winter. This week the E's AC started blowing warm air. Stopped while driving and checked both fans still working. Compressor sounds normal. Seems it will only cool one time when underway regardless of speed/idle. If you turn the fan speed up past half way it will kick on and stay on; however, if at any point you turn the fan speed down, it will not cool again. Mostly flat level ground, except an occassional bridge or overpass. Checked the forum couldn't find anyone with same or similar problem. What should I check next?

[Rick92040]

It might be low on freon.

[mdoneil]

I have to agree on the low refrigerant idea. Have someone with the proper reclamation machine check and fill it. Don't let some clown with a tank and a couple of hoses with gauges do it, do it right. I did it both ways and learned my lesson.