Lately I've noticed that the air conditioning in my '91
300D 2.5 doesn't cool very well while driving at less than freeway speeds. At first I wrote it off to the fact that the compressor simply isn't turning very fast at low engine RPM, and that the unprecedented heat wave the San Francisco area is going through right now is overpowering what would ordinarily be satisfactory A/C performance.However, I once had the same problem with a Toyota pickup I used to own. Then I discovered a small, knurled plastic knob under the dash marked "speed." I turned it all the way down (anticlockwise), and the probem was solved: all of a sudden the air conditioning blew cold even with the engine at idle.
Is there an equivalent adjustment that can be made on W124s?
Tired of sweating, Geoff