[W126 Coupe] central locking question

[Sharan Bains]

Hi Markus,

Do all doors lock if you lock from the passenger door ?

The CL pump has 3 wires coming into it - one from each actuator and there 
are 3 actuators on the w126 : one each in the front doors and one in the 
trunk.

When alarms are fitted they usually splice into the blue wire running from 
driver door to pump (wire from passenger door is green, trunk wire is 
yellow). One end of the spliced wire (the pump end) is connected to the 
alarm control unit which sends +12V/gorund to lock/unlock doors. The other 
end of the wire (drivers door side) also runs to the alarm unit, to complete 
the circuit...so that if you lock the drivers door via the key, then all 
doors and trunk/gas flap lock as well.

The fact that your alarm is not working the central locking and that your 
locking is not activated via the drivers door suggests that the circuitry in 
the alarm unit that controls the lock mechanism is faulty - or the wire 
running from alarm unit to CL pump is bad or has come loose at the alarm 
unit end. The alarm unit contains a circuit board with SPDT relays and timer 
relays to trigger the 3.5 second +12V/ground pulse required to lock/unlock 
doors.

Under the drivers side footmat, you should find a black plastic covering on 
the footwell area running along the door side - under that flap, you may see 
where the blue lock wire has been spliced into. The wire runs from the 
driver door to the pump - so passes under that area. It is probably that the 
solder joint has gone bad.

If you sit inside the car and activate your alarm by remote, can you hear 
any relays clicking ?  If so, your alarm is working and sending a signal - 
in which case the blue wire has no link to the pump.


talbir






>From: "Markus Meyer" <mfmeyer at iwon.com>
>Reply-To: mfmeyer at iwon.com,Mercedes Coupes Mailing Lists 
><mbcoupes at mbcoupes.com>
>To: mbcoupes at mbcoupes.com
>Subject: [W126 Coupe] central locking question
>Date: Mon,  6 Jun 2005 14:39:01 -0400 (EDT)
>
>  Hi gang, My 1987 560SEC recently started acting up where I realized the 
>remote for my alarm wasn't locking the driver's door.  This happened about 
>2 years ago and I replaced the vacuum pump in the trunk after swapping with 
>a known good one from a local fellow lister.  I'm just curious if I have 
>the same problem again or something else maybe? Driver's door will lock 
>with key, but only that door.  Everything will lock if I use the key in the 
>trunk.  Nothing will lock if I use the remote for the alarm.  I'm just 
>stumped why the trunk would lock everything but not the driver's door, and 
>how this could be the pump, wouldn't the pump work the door as well as the 
>trunk way? Thanks,Markus
>
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