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Trunk (Boot) light

Discussion in 'Z3 Roadster & Coupé' started by Don N, Dec 2, 2013.

  1. Don N

    Don N Dedicated Member

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    I thought I was so smart when I replaced the trunk light bulb in my new (to me) Z3. I did notice, briefly, when I removed the light, that the wires were not connected. I thought I might have pulled it out too roughly. So, I put in the new bulb, connected the wires, the light worked, and I closed the lid. I guess I was not surprised, when I next tried to start the car, to find the battery dead. After a jump start, all was fine. When this happened a second time, I realized that there was a problem. Likely the slight switch was faulty. But where is the switch?

    My new friends at the local BMW parts counter knew the answer - the light switch is built into the trunk latch mechanism. For the small price of about $50 and 15 minutes of my work, the new trunk latch is now installed. This time, when I put the light bulb into the holder, I could hear the micro-switch making and breaking. The problem seems to be solved.
     
  2. GazHyde

    GazHyde The Gaz Monkey
    Staff Member Administrator Global Moderator British Zeds

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    It's an all too common and very annoying issue this one. It's difficult to tell if the light is off when the boot lid is down.

    Easiest way to confirm it goes off is shutting your camera phone in the boot recording video. A quick playback should confirm the light is out.

    Nice to know its a simple and relatively inexpensive fix though.
     
  3. Don N

    Don N Dedicated Member

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    Thank you, GazHyde: The video camera (or wife) in the boot is a great idea. It proved why my battery went dead for a fourth time, yesterday. It turns out that there is an entire library of information on this problem in other forums, and probably somewhere in this one, as well.

    To condense: Apparently there is a spot in the wiring harness somewhere near the boot lid, where the wires flex, that is touching earth. This could prevent the new switch in the new latch from breaking the circuit. Operating the switch plunger in the new latch does not turn off the light. However, I believe the switch is trying to work because when I insert the light bulb into the socket, there is a clicking sound from the latch as the circuit is completed. This sound was not present before I changed the latch.

    I've removed the bulb.

    The hunt continues!
     
  4. GazHyde

    GazHyde The Gaz Monkey
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    The wiring loom issue is usually where the loom exits the trunk (or boot as we say in the UK!) and in to the trunk lid. If you look at the trunk hinges you should see where it's routed.

    You need to pull the insulating tape covering away from the cables and inspect them. It's not the easist to get at as the breaks tend to be just in side the hole.

    I'll try and take some pictures tomorrow in daylight, unless I find the ones which I know are on here!
     
  5. Aceman

    Aceman Moderator
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    If you are hearing a clicking sound from the latch when you insert the bulb then I suspect you do indeed have a short in the wiring loom as there is nothing associated with the boot lamp that would cause a clicking. I think the short could well be the central locking actuator clicking as a result of completing the circuit with the bulb and subsequent short across to one of the central locking wires.

    As Gary has said it is most likely to be the wiring inside the rubber sheaf on the left side of the boot lid that is damaged causing your problems and can also throw up some wierd and wonderful problems with the central locking so check that too. Hope you get it sorted and keep us all updated.
     
  6. Don N

    Don N Dedicated Member

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    Thanks so much, Gents. So far, the Central Locking is working correctly, but I am sure I can muck that up too!
     
  7. LicLic

    LicLic Newbie

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  8. LicLic

    LicLic Newbie

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    are the broken wires obvious after i cut the tubing off or can they be broke within their own insulation
     
  9. TaffZee

    TaffZee Zorg Guru (V)
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    This is a common problem with the Z3, I had to do mine due to problems with the central locking.

    See Here:
    http://zroadster.org/forum/threads/boot-wiring-loom-central-locking-issues.959/
     
  10. GazHyde

    GazHyde The Gaz Monkey
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    It depends but its usually its fairly obvious. only way to find out for sure is to strip back the tubing though.

    Welcome to ZRoadster.org by the way...
     
  11. t-tony

    t-tony Zorg Expert (I)
    Supporter British Zeds #ZedShed

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    This is a problem common to very many cars, particularly the VW group.
     

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