1995 BMW 740 Intermittent A/C

The subject is not quite accurate. The A/C works fine. What is intermittent is the blower.
It makes no bad noises, it always works in the morning or after a good rest; it just sometimes doesn't work on a re-start.
Mostly it will not work until the car sits for an hour or two. Occasionally it comes on after a 10-15 minutes of driving.
Turning the a/c switch and other controls on-off has no effect.
When off, a small amount of cold air still seeps through. The compressor clutch cycles on and off about every 30 seconds.
Yet I think it's a s sensor or switch rather than the entire blower (fingers crossed). Grady