W124 central locking advice please

howiiix

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My central locking will not work from the drivers door but is fine from passenger door. I have taken everything apart but would like to know which item actually triggers the cl function - is it the contacts inside the actuator itself? The lock itself has a microswitch which I can hear clicking when I turn the key but an earlier car I have examined does not have this and its central locking is ok therefore I guess this is for another function?
Any help much appreciated.
 

wireman

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nice 201 2.5D 1993 & very nice 129 SL500 1994
On my 1989 124 there is-
A pump which blows the locks on and sucks them to unlock. Its under the rear seat.
A belows on each door, the boot and filler cap. The diaphragms in these can split.
A switch on each front and the boot locks. They can be a bit weak, take the door card off and its hiding near the lock, connected to 3 wires.

The switches are energised momentarily and signal to the pump unit whats required, ie lock/unlock, a presure switch and timer also in the pump sort out how long the pump runs for (up to 15 secs), the pressure or vac is sent to all the locks via yellow 5mm tubes.

The wires from the switch pass through the rubber belows between door and post this is a common fail point for window wiring so your locks may be similarly affected by broken wires here.
 
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howiiix

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Thank you for the info. I have stripped the wire cover off and found that the three wires had fused together (too much current?), I guess this is my problem although I am not looking forward to feeding new cable up through the door / post.
What function does the microswitch in the lock itself fulfill; it clicks as I turn the key both to lock and unlock the door. It has a two pin plug with two small diameter wires heading off through the door / post interface. Last evening it started whirring like mad, I had to disconnect the battery - any ideas?
 

television

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2002 SL500, 216 CL500, all fully loaded
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howiiix

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Thank you Malcolm. Looking at the diagrams I deduce that the microswitch (which is inside the metal lock plate itself) is related to an anti burglary system; mine is a 1994 car with "MB approved alarm system". I have disembled the central locking from an 1989 car in our local scrapper; this does not have the lock microswitch but the cl works ok. All the above leads me to believe that my problem is in the wiring from the 3 pin plug on the cl bellow actuator. Please revert if you think I have missed something! Thanks again.
 

television

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There has to be a switch in all of the lockable ones, in order to run the PSE pump
 
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