Hi, Does anyone could tell me what this vacuum line purpose? Where does it connected to? It's taken from 2001 E240 Avantgarde. When I bought the car, the pipelines were disconnected. I don't know what is the consequences if the pipeline was disconnected. However, I'm sure that MB won't bother put those pipeline if there are no good for it. I connect the pipeline but something strange happened. It turns out that there are whirring sound come from AC ventilation when the car is decelerate. I disconnect the pipe, and the sound gone. I guess this is why the previous owner doesn't connect the pipe. If anybody knows about this pipelines please tell me. Thank you very much.