So, are you saying that the door close assist pump runs at regular intervals while the engine is running and that's normal? The door close assist pump is the one that I'm hearing (on top of the left rear wheel well).

Aren't all of those other functions, like the HVAC control, central locks, and lumbar pillows operated off of the PSE pump under the rear right passenger seat?

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Mark S.
Seattle

1998 Mercedes S420, Smoke Silver, 138K