Squirly Problems with CLS Central Lock
 

I'm having some weird problems with the CLS on a 1989 300E.

First, I have noticed a new noise, like the humming of a small motor near
the right rear seat/door. This was not there for 20 years. Now it is, and
the CLS (when it operates) is weird.

Known problem: Removing the trunk hatch near the lock mechanism shows
the tail/push rod from the lock to an actuator. This threaded rod seems to
NOT be held tightly in place, like the plastic part is galled. (I need to replace/fix).

The 3rd observation, is that the key will not activate the lock on all doors.
The driver door will open, and maybe the 2 rear doors (& always gas lid and
trunk), but never the passenger door. However, if the car is open, or locked,
then using the key in the passenger door will open ALL doors (& gas & trunk.).
(I suspect a broken wire or contact on a door switch.)

I also can activate the CLS fully from the passenger door many, many
times, so the system appears to be holding good vacuum.

I assume that the motor whine is the vacuum motor? But why now ?

I would like to buy a CLS diagram (on CD OK... Where?, from whom?)
Such that I can troubleshoot the logic. And find location of parts....
BEFORE I blindly tear open 4 door panels !!! Also I have not been able
to find the trunk actuator on the Internet/parts supplier (the door actuators,
however are readily available.)

Any help appreciated. Especially place to buy diagram and parts!

the humming is most likely the Vac pump. I believe it's in that general area.