I had a related issue today. Warm day in the Northeast; probably around 90 with dew point at 70 or so. Turned on the A/C through the manual settings. A/C worked for 10 miles or so, then lower fan power and no cold air. Played with the different settings trying to get cold air, but no dice. Finally turned off climate system and back on again, which seemed to solve the problem. Worked fine in the "auto" setting later in the day, set at 75, outside temp around 93.
Any thoughts?