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