I own a Mercedes 1990 560 SEL. My problem is that my heat/AC stopped blowing.
If I turn all climate control buttons off and let car sit several days and
then turn on defrost the unit will start up and both heat and AC will work
for a short time (sometimes seconds other times minutes) and then shut down.
Of course if I have the heat control buttons on and drive down the road at a
good speed heat will come out of the vents but blower will not be working.
When switching control buttons I do hear the compressor engaging even though
fan is not blowing air. I thought it might be the blower moter or blower
regulator or heater moter but I am puzzled becasue it will occasionally work.
This happened last year the same way and them in summer it began working
again and lasted almost the whole summer season and then shut down-Bizaare????
If anyone knows what this could possibly be I would really appreciate your
expertise.

Thanks