Well a few more days of driving and the vents closing unexpectedly problem contutinues to be intermittant. I've had someone suggest that the climate control unit may be the problem.
To my mind vacum seems to be an all or nothing thing like being pregnant. (I may be quite wrong.) The intermittenant nature of this problem may indicate something else.
I also determined that the econ switch doesn't turn off the compressor, i.e. I still get freezing cold air with the econ button pressed.
Is there a sure and simple way to determine that the climate control or the vacum is the problem?
'87 300TD Turbo