Mercedes Repair Questions? Ask a Mechanic for Answers ASAP
The vacuum hose (if it has one) hooks straight into an intake manifold vacuum port below the throttle.
Maybe you have the wrong part? The part number for the regulator is(NNN) NNN-NNNN and it cost $460.00, through Mercedes
Here are the instructions from Mercedes on how to change it. Notice they say nothing about vacuum. There is not anything in the vacuum diagrams about it, either: