W168-Randomly locking/unlocking and alarm

Discussion in 'Electronics' started by Harrinho, Jun 6, 2017.

  1. Harrinho

    Harrinho New Member

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    Jun 6, 2017
    Car:
    A170 (W168)
    Hi Everyone,

    I have a quite annoying issue with my W168 (A170). While I'm driving and am on the move the car locks and unlocks and the indoor lights turn on. The latest probably related issue is that when I have parked and turned the engine off, it starts ringing the alarm and the hazardous warning lights which caused the breakdown of the battery.

    I'm attaching the battery panel and the information page for relays and fuses. Could anyone give some help on which of the relays/fuses function the locking system and the security alarm?

    Cheers - Harris
     

    Attached Files:

  2. Auto-mobile

    Auto-mobile Hardcore MB Enthusiast

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    How old is car? Might be a faulty alarm system, on early cars these were fitted at the dealership, I have had a few go faulty over the years, also check all the door pin switchs to see if any are damaged, failing that the central locking pump may be faulty, it's in grey foam behind the spare in the boot.
     
  3. OP
    OP
    Harrinho

    Harrinho New Member

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    A170 (W168)
    Thanks for the reply. It's quite old, 2004 model.I'll check the recommendations and get back to you with any findings.
     
  4. Abb

    Abb Hardcore MB Enthusiast

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  5. GLK

    GLK Hardcore MB Enthusiast

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    Hello and welcome!

    If you car, by any chance, came with two (or even one) plastic "keys" that look like a slimline USB stick, one red, one black, then you can de-activate the alarm - the socket is inside the glove box, usually on the left side near the top.
     
  6. OP
    OP
    Harrinho

    Harrinho New Member

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    Car:
    A170 (W168)
    Thanks everyone for your replies. Yeah, I've gone through Albert Rowe's page but without success. Regarding the keys, I guess I don't have what you describe. Please see attached.

    The thing is that a couple of months ago it started doing this strange lock/unlock thing and today i noticed that the anti-theft alarm is enabled when the car is parked and locked and the hazards keep flashing. I had to unlock and lock it again, tried both manually and with the knob. It didn't do it again but who guarantees that it won't do it during the night for example.

    That's why I was wondering if it is any of the fuses I can put out so as to a) disable the anti-theft alarm and/or b) check the central locking
     

    Attached Files:

  7. GLK

    GLK Hardcore MB Enthusiast

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    This is what I was talking about:

    [​IMG]

    It is on the page Abb referred to above:

    Bert Rowe's-A-class info. Information A160/Feb 2002 Scorpion Car Alarm System.

    The red key:

    [​IMG]

    And the black one:

    [​IMG]

    That page also got a link to Scorpion, although I'm not sure they still able to help / support the system.

    Here's the fuse chart, with my own notes, you can try fuse 35, although I'm not sure the ECU will be happy, if you just remove it. I might be wrong ...

    [​IMG]
     
  8. Dec

    Dec Hardcore MB Enthusiast

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    The siren is 13 years old, it's very likely it is the cause of the fault.

    Unlock the car with the remote, this will disarm the alarm.
    Locate the alarm siren, unplug it and remove it from the car, it can still go off even when unplugged because it has its own battery power supply.

    See what difference this makes to the locking fault.

    Dec
     
  9. Auto-mobile

    Auto-mobile Hardcore MB Enthusiast

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    Your car will have factory fit, you won't have a scorpion aftermarket alarm and you won't have the black/red keys to switch it off.

    I'd deffinatley check the door pin switches to see if a seatbelt getting caught in the door has smashed one, also get a diagnostic machine plugged in to check for faults, not replaced a faulty siren on a w168.
     
  10. area51

    area51 Hardcore MB Enthusiast

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    Don't forget to check the tailgate switch.

    Does your car have a red led somewhere on the dash? If it does then next time the alarm goes off; press unlock on the key (alarm should then stop); place key in ignition and turn to position 2 (dash warning lights on); immediately check the red led which might flash, this will give an indication of where the alarm fault is.

    2 flashes-pause-2 flashes-pause.... is interior sensors for example.

    Hope this helps
     
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