Hi..
I'm actually posting this for a friend of mine, as my 76 450SL has a different locking system. He is having troubles with the central locking system. At present, the only way he can lock/unlock his car is to use the trunk lock. Both the driver and passenger side locks will not turn (I'm assuming it is a lock cylinder problem...both worn out).

In addition, when the vacuum pump kicks on it remains on for close to a full minute. So...if you are in the car, push down on the driver's lock...you cannot unlock any door for one minute...when the pump kicks off...the doors can unlock.

My theory is that my mechanically inclined friend did not realize that the pump was doing this...in an effort to unlock/lock too quickly...he messed up both lock cylinders.

So..need advice about the pump...what would cause it to keep running for so long? After I knock out that issue, we can see what is up with the cylinders...but I bet we need to swap those out.
Thanks!

A leak in the vacuum/pressure line from the pump. The pump turns off when pressure builds in the line, so a leaky line will let it run on. The lock actuators are often the culprit.

Steve

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'91 MB 190E 2.3
'08 RAV4 Ltd 3.5
'83 Lazy Daze m'home 5.7

im gunna revive this old thread.


i have the same problem in my 1992 190E 2.3



the rear door locks dont go down when you lock the car. and the pump stays on for around a minute.


where are the vacuum lines for the doors on this car?

Yellow, from the rear seat through the floor wiring ducts to all four doors.

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Gone to the dark side

- Jeff