Rear Door Central Locking Problem - not Solenoid
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Thread: Rear Door Central Locking Problem - not Solenoid

  1. #1
    Saab Afficionado
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    Apr 2002
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    Coventry, UK.
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    1,908
    Folks,

    Have searched threads but couldn't see anything on this... much appreciate any suggestions, especially based on hands on experience..:

    Rear N/S door intermittently fails to lock. I bought pack of four 2nd hand solenoids, and changed door unit, but exactly same scenario. Changed unit again for another spare 2nd hand unit, and lubricated all in-door mechanisms, but still exactly same problem.

    All other doors work fine. Wiring at solenoid end is fine. Mechanism feels fairly free, with no apparent stiffness or anything seeming to catch or get stuck.

    Interestingly, a month after changing to 2nd unit sympton improved (from approx 1 in 3 failure rate to approx 1 in 6). But when changing to 3rd unit problem now occurs every 1st attempt to lock door... If I then unlock and relock it normally now locks on 2nd attempt...!

    Seems strange.. hardly likely to be a broken/fatigued wire.. and unlickly to be 3 different solenoids (incl the original unit).

    Is their anything in the door mechanism that can stick/jam to cause this effetc or other know causes?

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  3. #2
    I usually find that if the rear doors fail to lock/unlock consistantly (assuming everything is OK electrically) the cause is that one of the pivot points falls out of its hole. There are two for each lock. They are located at either end of the horizontal rod that runs the length of the door just under the glass. It seems that the after (rear) one, back by the solenoid, pops out more often. If the front one is out, the lock button offers no resistance to up and down motion. These can be replaced with a homemade 1/4" bolt /nylock nut assembly.

    Just make sure that the child safety locks are functioning correctly and are in the correct position.

    Try another central locking module if you have one or re-flow the soldered connections on the one you have,

  4. #3
    Saab Afficionado
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    Thanks Chengny,

    By way of the horizontal rod, i understand you mean the one which connects the door lock button/knob to the door lock unit. The two pivots which hold this are fine. I also checked the child safety lock operation. Everything looked fine from what I could see. I'm certain it cannot be the solenoid, as 3 units with same effect is v-unlikely...

    But the situation has developed somewhat...

    Now, every time I unlock the door (using remote), it fails to work first time (except for the other 3 doors - which continue to operate normally), and rear near side door lock button/knob fails to move. But then when I re-lock (using remote) it works second time I press unlock button on remote. This second time scenario is now constantly occuring..!!!

    Seems completely bizarre... except that there must be a mechanical or electrical root cause to explain the constent phenomena. Can't be chance, or just a bad connection... maybe the electronic control unit is going bonkers..!

    Has anyone else ever experienced this scenario?

    What are the odds I need a new central locking control unit?

  5. #4
    Foolproof way of checking solenoid is to swap it with the other side, can be sure one way or another then, eliminates one possibility, but sorry can't help with any other points!

  6. #5
    Saab Afficionado
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    Arrow

    Good point Steve.
    Nice thing about the 9000 is most parts are easily accessible and changeable, including door solenoids. Some car solenoids I've lookedat required window glass removal.. and all sorts of gymnastics to remove.

    Fault now starting to subside again.. with any luck it will just go away!!

    Otherwise I will swap solenoids then maybe try to trace wiring through door... before the possibility of concludign the central control unit is playing up - unless anyone else has seen a similar scenario and ID'ed cause.

  7. #6
    I don't believe the electromagnetic lock solenoids .. Ever.. fail. It's just a coil and a slug. I've yet to see a genuine 'dead' one .. but?
    Usually it's a fault with the controller unit, or even the key fob batteries, unlikely as that seems.
    Occaisionally simply unplugging the Controller and replugging it clears the problem. These controllers are the same(?)part for all saabs back to early eighties.
    Might be due to connector oxidation or? but it has worked before... try it?

  8. #7
    Saab Afficionado
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    Sounds like another slick trick...

    Can anyone advise where the Central Locking Control Unit is located on a 1998 car?

    Are there any issues disconnecting and reconnecting with the battery still connected?

    Presumably I will just have to press remote up to 5 times to resynch unit...?

    Thanks in advance.

  9. #8
    Presumably I will just have to press remote up to 5 times to resynch unit...?[/b]



    That's why I don't like disconnecting the battery, connecting it up it immediately started to go off and frantic pressing of the fob did quieten it!!


    My solenoid was failing, whether it was the mechanism wearing out instead of the pin/coil I don't know as I never pulled it apart, couldn't be bothered to be honest lol

    These may be of help with where the control is and maybe even something else to think off, if the reed switch isn't telling that the door is shut then maybe it won't lock? Never tried to be honest if it will lock with the door open?

    This is mentioned here:

    http://www.uksaabs.eu/UKS/viewtopic.php?f=2&t=13922

    Older car and is left hand drive but maybe of help:

    http://www.saabcentral.com/forums/sh...d.php?t=131683

    And what the EPC says: part 1, looks like the cowling under the steering column?




  10. #9
    Motor Mouth
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    Oct 2002
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    Kippen, Stirling
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    Steve,

    The reedswitch controling the pictogram has no connection with the locking mechanism. The doors ( except the driver's ) will 'lock' ie the plunger will drop, if the fob is pressed even with the doors open. When closed, even the the 'half latched' position, the lock will prevent the door being opened again.

    Paul @ Kippen.

  11. #10
    That's why I don't like disconnecting the battery, connecting it up it immediately started to go off and frantic pressing of the fob did quieten it!![/b]
    Clearly you have issues with your locks/alarm.
    I don't believe it should not do 'that' . Mine for example, does not.
    One can test the integrity of the locking system by accessing the Drivers door wiring (Door edge connector block?) Locks are activated when 'ground' is supplied. Short the ground wire to the metal door and the locks will work.. signifying that the problem is neither in the Solenoids nor their wiring

  12. #11
    You can bench test the lock motors/solenoids with a battery charger. It is nice because you can do it a million times while troubleshooting an intermitent failure issue. Also you can watch it's snap action up close and use your finger tip to apply a load that simulates the resistance of the linkage.

    Just be sure not to leave the test leads connected for more than a blink of an eye. Prolonged application of power can easily fry the coils.

    When being operated normally, i.e. by the central locking module it (the CLM) only energizes them (actually it grounds them) for .7 sec.

    Are all your "door ajar" lights on the pictogram operating? The feedback from the doors as to whether they are open is critical to the operation of the locking circuit. In addition to the plunger switch mounted in the pillar at each door hinge, there are also proximity type switches in the actual door locks themselves (except the drivers lock). These are also involved somehow. I started to try and figure out what they do at one time a few months ago.

    Never had to to however, because it turned out to be a series of three (3!!) malfunctioning central locking modules. Granted, they were all from the junkyard, but 3 bad ones in a row? Jeez! Talk about throwing a monkey wrench into my troubleshooting logic.

    The way I found out that it was not the solenoid but rather the CLM was by the bench test method. And that's when I looked at the condition of the pin/PCB interface on the three CLM's with a magnifying glass. All of them had fractures through the solder joints, mostly near the outer edges. After killing myself for 3 days, it took only 5 minutes with a pencil type soldering iron and all of them worked every time and have since.

    Note to Paul Kippen: I missed your advice on the reed switches (that I called proximity switches). Sorry.

  13. #12
    The other common failure mode of the central locking module is the small solenoids on the printed circuit board going bad. The internal contacts burn up giving you the same intermittend weather depended central locking problems as poor soldering joints. You can easily replace them if you know how to handle a soldering iron and if you can get some that will fit on the pcb.

  14. #13
    I find that my rear drivers side lock periodically stops working from time to time. What I am doing at the moment is "jiggling" the connector plug that connects to the rear door between the front and rear door. I also spray the connections with a special spray that is designed to clean/improve electrical connections (I got this from the local auto shop). This seems to fix the problem, at least for a while - I then do it again.

  15. #14
    Saab Anorak
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    Sep 2003
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    Bonzo, I have always found that that is the lock which give problems first on my cars. It is normally down to lack of lubrication on the various joints on the mechanism. Cleaning the connector with contact cleaner might help if there is a problem, but I would suggest removing the door card and lubricating all the joints (be careful of the bell crank connection to the lock button when removing the card, they break!).

  16. #15
    Saab Afficionado
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    Thanks for all the excellent feedback - as usual.

    Just thought I’d update this thread to help others find the Central Locking Control Module on a 1997/8 model 9000. I discovered location info is extremely sparse, especially after receiving some dud information from one second hand Saab specialist, and discovering Haynes Manual does not define where the module is located.

    For my vehicle, module is located above throttle peddle (although I note owner of older 9000's report it as being above clutch pedal) on my right-hand drive vehicle). Extremely easy to get to AND remove (unlike reports for some older 9000's).

    To remove insulation panel above drivers foot pedals..:
    Instead of pushing the inner pins of plastic securing plugs, as Haynes Manual advises, and which doesn’t always result in easy retaining plug removal, I used a thin pointed tool to pull the head of the centre pin of the securing plug back out of the plug. This resulted in easy removal of plugs (which can be re-used), and insulation panel.

    Removal of Central Locking Module (CLM)
    Unlike some older models of 9000, the unit was visible and easily accessible (on a 1997/8 model 9000) looking straight up, as is the single securing clip. The unit is a black plastic box about 5” long and approx 1.5” across. My part number is: 410285140505359.

    The sprung securing clip is friction fit. To remove, just pull it back, to release plastic peg fixed to CLM module case. The Control module then lifts up off from the plastic tray above which it sits. It can then be easily lifted over side of the tray and dropped down into floor well area on cable.

    Unfortunately cleaning up the connector spade ends did not solve my intermittent rear door ‘failing to lock’ problem. Whilst I couldn’t see any cracks on the main PCB/connector pin joints, next step is to re-solder this area, then if unsuccessful, I’ll will try some freezer spray + heater gun to check if problem is actually on the Control module.
    Incidentally, if anyone decides they need a Central Locking Control Module repair specialist, found I happened across this one..: http://www.tempomat-vdo.de/keywords3.html

    Could be handy as I was quoted £270 (inc vat) for replacement unit ‘new’ and £60 for 2nd hand, from a non-franchised Saab specialist.


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