Peter, your efforts are greatly appreciated, thank you! Your reply seems to confound the problem even further...I didn't notice any other distribution block under the passenger footwell plate, especially one with 15 ports! I guess I will need to dig deeper. You are right though, if these are all HVAC flaps, what does the transmission shift lever have to do with anything? Trust me though, the pump runs [I]only[I] when placed into a forward gear. To answer your other question, no, the central locking system did not come back up with the grey/green port plugged. But, after using the MightyVac to test all of the lines I discovered that all but the driver's door tubing is good and holds a vacuum....and I can lock/unlock the doors (except for the driver's) and trunk and gas filler door using the tool. Also, using the key in the trunk locks and unlocks all of the doors but the driver's. So, I obviously have a secondary problem with the driver's door locking/vacuum mechanism. Ah, life with a 140 is indeed an experience! If the car wasn't so damned nice I would sell it.......nah.

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1996 SL320 97K miles
1996 C220 130k miles
1992 500SEL 170k miles <---sold
1986 300E 216k miles <---sold