Neal

Brian's comments are right on.

The low pressure switch is in series between the ACC and Klima; I would check for ground at the low pressure switch when calling for AC. If none, I think the ACC pushputton unit is the culprit (barring a wiring problem, which seems unlikely).

As an aside, I had a bad Klima (and I know I everyone says these never go bad) on my '87 SDL. My symptons, however, were different from yours: A/C would just cut randomly as if it were a speed sensor problem.

__________________
as ever
Paul

1989 560SL
1987 300SDL
1987 300TD
1983 BMW 633CSi
1972 280SE 4.5