I posted this in your other thread about the same subject.
http://www.peachparts.com/shopforum/diesel-discussion/380147-83-240d-climate-control-vacuum-leak.html#post3627967
There is a air recircualtion flap that is controlled by vacuum on a 240D. I believe the green line goes to an electrical switch overvalve and then leads to the vacuum pod.
It's all behind the glove compartment box and remove the dashboard knee panel to see the line.