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Thread: BMW Z4 GM5 Temporarily fixed in 3 steps

  1. #1
    Join Date
    Jul 2015
    Location
    Desert, AZ
    Posts
    6
    My Cars
    2004 E85

    BMW Z4 GM5 Temporarily fixed in 3 steps

    Firstly, I'd like to say there is A LOT of misinformation out there regarding the Zed 4's lock problem. I read false things about duct taping cables to doors, new actuators, lubricating mechanics to alleviate this problem. I feel bad for those without a mechanical or electrical inclination who could not deduce this information as false. For those also lacking knowledge, this is obviously a temporary fix geared toward semi-skilled people. The real fix is new relays OR a new GM5 with good working relays programmed to your car. Here is how I fixed my Grundmodul V.

    For you turbo readers who want the quick answer like I did on my journey here are your simple steps:
    1. Remove the GM5.

    2. Clean the relay contacts and bend the contacts closer.

    3. Reinstall the GM5.


    Here is what relay looks like topless:





    Tools for the repair:
    •Screwdriver to remove the GM5
    •Cutting tool to remove the relay's hat
    •Prying tool to bend the contacts closer
    •Cleaning solution and wipe for relay contacts

    Details on the 3 Steps:

    Epic disclaimer: be careful not to Electrostatically Discharge on your board or across connector contacts or across IC's or any board components.

    1. Removing the GM5: I followed a video on YouTube for a different car and wasted time in the scorching desert sun removing my glovebox. Don't do this. You only need to remove 2 screws and lower the passenger kick panel. Very easy. There are lots of videos and resources to help you remove the GM5, which again is easy.

    2. 2.a Gently remove the top of the relay using your careful creative means. This is not a job for fat fingered people- I love you guys, but surgery is not your forte. This is also not a job for the impatient. You may think "ooh quick easy fix, let me make it quicker with my carelessness", but that is how you end up with a dark, unlocked car. Another user on this forum mentioned he CAREFULLY did this with a dremel.

    2.b Use contact cleaner and thin cleaning pads to clean the contacts. Or use slivers of paper and alcohol .

    2.c gently bend the contacts which are not touching the relay armature in and take care to leave a gap .

    3. Put the GM5 back in.

    Other things I tried:
    1. Reheating the solder on all relay contacts. I did this in case any micro fractures were causing the failure. This did not work.

    2. Cleaning the contacts. Nope cleaning did not work.

    When did my GM5 die and how?
    My locks started acting up after I left the car in the extremely hot desert sun for 6 hours.

    Why did I do this strange "repair"?
    I did this as a form of troubleshooting before I bothered with replacing the relays. Now thanks to this experience I have confirmed this was MECHANICAL issue of an ELECTRICAL part.


    MYTHBUSTING
    Why did I make fun of all the other repairs I saw online?

    Stretched cables? Ok look, using some critical thinking, if the lock cable "stretched in the summer sun" (as some say) why didn't this happen at other times in similar conditions? And both doors, really, at the same time? No, this is a not 1 door mechanical issue that happens to both doors simultaneously. That sounds ridiculous.

    Bad actuators? Odd that both actuators died simultaneously even though the passenger actuator is rarely ever actuated. Hence, another nope.

    The window smashed the cable? Ok, so all those times I rolled my windows up and down was fine but now after the car sits BOTH locks were crushed by stationary windows? Another crazy BMW wives tale.

    The thingies are dry and you need to lube them? Ok... both doors at the same time dried out, and the most used door is OK, while the other is mute. Nope.

    Disclaimer: this is not a real fix, it was a troubleshooting experiment. I take no responsibility if this doesn't work for you or if you destroy your car or pieces of it.

    Helpful resources:
    This explanation and somewhat schematic:
    http://www.bmwgm5.com/Door_lock_schematic.htm

    All the other posts telling you how to remove a GM5.

    Googling the parts of a relay.

    Additional comments:
    Yes I used silly tools to accomplish this repair almost to make a point to the DIYers. However, I do have some real tools and experience just on the borders of those photos that you can't see. Be careful when doing this work. If you're doing this to your car to save money, but you are not handy I highly recommend you leave the repairs to the professionals such as the mail-in services offered for GM5 repair.

  2. #2
    Join Date
    Feb 2008
    Location
    Pac.NW
    Posts
    4,949
    My Cars
    '03 Z4, '85 Subaru Wagon, '87 Suzuki Savage LS650
    Quote Originally Posted by Bitte Angurten View Post
    Firstly, I'd like to say there is A LOT of misinformation out there regarding the Zed 4's lock problem.
    Hmm...I sacrificed a chicken at midnight on the summer solstice and this did the trick for me. I think blood rites are a neglected solution for many problems these days.
    Not so much a signature as a cry for help.

    Hold on, saw this in a cartoon once...think I can pull it off.

  3. #3
    Join Date
    Jun 2011
    Location
    Saint Charles
    Posts
    3
    My Cars
    2003 Z4 2.5i
    That worked great. 11.jpg12.jpg13.jpg

  4. #4
    Join Date
    Dec 2013
    Location
    Chicagoland area
    Posts
    4,372
    My Cars
    EXOTICS
    I would like to add some actual true information, no myths to this thread,
    by providing a link to another one here:https://www.bimmerforums.com/forum/s...&highlight=GM5

  5. #5
    Join Date
    Aug 2012
    Location
    Wilmington, DE
    Posts
    14
    My Cars
    2004 BMW 330xi
    For that amount of effort you may as well just replace the relays. They are easily purchased and are very cheap. Although I did enjoy looking under the covers of them.

    Sent from my Pixel 2 using Tapatalk

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