[W126 Coupe] central locking question

Sharan Bains sharanbains at hotmail.com
Mon Jun 6 16:13:46 EDT 2005


Markus,

Yes, easy to verify if it is the pump.

Remove the 3 prong connector (which has the blue/yellow/green wires). 
Connect a wire to ground at one end and then (with the doors open and keys 
in your pocket) touch the wire on one of the 3 terminals on the pump. No 
matter which terminal you touch, doors should lock (since a 3 second ground 
signal locks doors). Test each of the 3 terminals on the pump 
turn-by-turn...if doors lock from all three terminals on the pump, then pump 
is fine - then you know it's the alarm unit/connections from it that are the 
culprit.


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: RE: [W126 Coupe] central locking question
>Date: Mon,  6 Jun 2005 16:07:23 -0400 (EDT)
>
>  Thanks for all the replies so far... I just checked and the driver's door 
>only locks/unlocks itself. The trunk locks/unlocks all 3. The pass door 
>locks/unlocks all 3. Sitting in the car, all closed and unlocked, when 
>clicking remote, I hear the chirp of the alarm, then a clicking/vacuum kind 
>of noise in the door, then silence, then another clicking/vacuum in the 
>door again, and possibly something going on in the pass footwell but didn't 
>sit on that side of the car. So I guess Talbir is pointing me to an 
>electrical fault.  Later on after my workout and dinner I'll pull the pass 
>side apart and see if I find wires being spliced in and all.  I'm just 
>suspicious that this same thing happened two years ago and swapping the 
>vacuum pump cured it until now....seems odd because if it were electrical 
>all along, why would that have worked?  Of course I don't know that I 
>tested all 3 access points back then to know what worked/didn't back then 
>and I may truly have had a bad pump back
>then and not now. Thanks,Markus --- On Mon 06/06, Sharan Bains &lt; 
>sharanbains at hotmail.com &gt; wrote:From: Sharan Bains [mailto: 
>sharanbains at hotmail.com]To: mbcoupes at mbcoupes.comDate: Mon, 06 Jun 2005 
>19:55:25 +0000Subject: RE: [W126 Coupe] central locking questionJust a 
>further note - if locking works from trunk/pass door, and all doors lock 
>when you lock from one of these points, then you don't have a vacuum leak. 
>It's an electrical fault you are looking for.talbir&gt;From: "Sharan Bains" 
>&gt;Reply-To: Mercedes Coupes Mailing Lists &gt;To: 
>mbcoupes at mbcoupes.com&gt;Subject: RE: [W126 Coupe] central locking 
>question&gt;Date: Mon, 06 Jun 2005 19:45:28 +0000&gt;&gt;Hi 
>Markus,&gt;&gt;Do all doors lock if you lock from the passenger door 
>?&gt;&gt;The CL pump has 3 wires coming into it - one from each actuator 
>and there &gt;are 3 actuators on the w126 : one each in the front doors and 
>one in the &gt;trunk.&gt;&gt;When alarms are fitted they usually splice 
>into the blue wire
>running from &gt;driver door to pump (wire from passenger door is green, 
>trunk wire is &gt;yellow). One end of the spliced wire (the pump end) is 
>connected to the &gt;alarm control unit which sends +12V/gorund to 
>lock/unlock doors. The other &gt;end of the wire (drivers door side) also 
>runs to the alarm unit, to &gt;complete the circuit...so that if you lock 
>the drivers door via the key, &gt;then all doors and trunk/gas flap lock as 
>well.&gt;&gt;The fact that your alarm is not working the central locking 
>and that your &gt;locking is not activated via the drivers door suggests 
>that the circuitry &gt;in the alarm unit that controls the lock mechanism 
>is faulty - or the wire &gt;running from alarm unit to CL pump is bad or 
>has come loose at the alarm &gt;unit end. The alarm unit contains a circuit 
>board with SPDT relays and &gt;timer relays to trigger the 3.5 second 
>+12V/ground pulse required to &gt;lock/unlock doors.&gt;&gt;Under the 
>drivers side footmat, you should find a
>black plastic covering on &gt;the footwell area running along the door side 
>- under that flap, you may &gt;see where the blue lock wire has been 
>spliced into. The wire runs from the &gt;driver door to the pump - so 
>passes under that area. It is probably that &gt;the solder joint has gone 
>bad.&gt;&gt;If you sit inside the car and activate your alarm by remote, 
>can you hear &gt;any relays clicking ? If so, your alarm is working and 
>sending a signal - &gt;in which case the blue wire has no link to the 
>pump.&gt;&gt;&gt;talbir&gt;&gt;&gt;&gt;&gt;&gt;&gt;&gt;From: "Markus Meyer" 
>&gt;&gt;Reply-To: mfmeyer at iwon.com,Mercedes Coupes Mailing Lists 
>&gt;&gt;&gt;&gt;To: mbcoupes at mbcoupes.com&gt;&gt;Subject: [W126 Coupe] 
>central locking question&gt;&gt;Date: Mon, 6 Jun 2005 14:39:01 -0400 
>(EDT)&gt;&gt;&gt;&gt; Hi gang, My 1987 560SEC recently started acting up 
>where I realized the &gt;&gt;remote for my alarm wasn't locking the 
>driver's door. This happened about &gt;&gt;2 years ago and I
>replaced the vacuum pump in the trunk after swapping &gt;&gt;with a known 
>good one from a local fellow lister. I'm just curious if I &gt;&gt;have the 
>same problem again or something else maybe? Driver's door will &gt;&gt;lock 
>with key, but only that door. Everything will lock if I use the key 
>&gt;&gt;in the trunk. Nothing will lock if I use the remote for the alarm. 
>I'm &gt;&gt;just stumped why the trunk would lock everything but not the 
>driver's &gt;&gt;door, and how this could be the pump, wouldn't the pump 
>work the door as &gt;&gt;well as the trunk way? 
>Thanks,Markus&gt;&gt;&gt;&gt;_______________________________________________&gt;&gt;&gt;&gt;The 
>MB Coupes Website!&gt;&gt;W126 SEC Mailing List&gt;&gt;Postings remain 
>property of MB Coupes, L.L.C.&gt;&gt;&gt;The MB Coupes Website!&gt;W126 SEC 
>Mailing List&gt;Postings remain property of MB Coupes, L.L.C.The MB Coupes 
>Website!W126 SEC Mailing ListPostings remain property of MB Coupes, L.L.C.
>
>_______________________________________________
>
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