You have a large vacuum leak or most probably leaks somewhere in the system- could be just about anywhere. This is common with older C3s, there's lots of online troubleshooting guides available that will walk you through the system in a progressive, logical manner to track them all down.
Try first examining the seals at the front of each headlight actuator.
for more information than you would probably want related to headlight vacuum restoration and or repairs, do a search here on the subject and you will be overwhelmed by what will pop up. it has been discussed and many suggestions offered repeatedly on this site.
Thanks! I hadn't thought of that. I know there is a 'manual' that you can buy - I haven't gotten around to fooling with it anymore for a while....but still researching. I also know that Eckler's has the entire 'kit' to do both actuators for $34.95....