E90/91 blower recall info - my descovery...pic inside

Discussion in '3 Series' started by OHP, Dec 9, 2018.

  1. OHP
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    OHP

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    So after still trying to trace why my front passenger window isn't working...

    I'm aware of the recall for the blower motor so whilst I was digging around I decided to check the terminals and low n behold I have the issue....

    Now I haven't smelled any burning only time I noticed an issue was when it stopped working intermittently when really cold last year about the same time my window died...

    Now for those of you who have received the notice and putting it off I'd deffinately suggest getting it sorted before we get a big freeze again and it causes a fire

    IMG_20181209_220044.jpg
     
    Last edited: Dec 11, 2018
  2. Adie
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    Adie WARLORD Site Supporter

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    Well spotted, could have resulted in a nasty outcome. Perhaps the blower jammed causing the wires to overheat? The fuse doesn't seem to be doing it's job.

    Hope you manage to fix the window.
     
  3. gw8izr
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    gw8izr

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    Failures of that type are not entirely related to the load connected. The crimp has been badly terminated, stressed, strained or partly separated from the mating terminal.

    The defect has increased the contact resistance. The current flowing in that joint has caused it to heat, almost straight away the heat causes the crimp to further relax and the contact resistance further increases. The increased resistance causes an exponential increase in heat dissipation and localised damage ensues.

    Had the blower jammed (or whatever the load is) and the fuse failed to blow the heat damage would have been spread along the cable not localised to the joint.

    As the resistance increases the current actually decreases which is why the fuse doesn’t blow, the failure is increased I2R losses in the joint not increased current.

    As an aside If you were to measure the resistance of that joint using a small current tester such as a DVM it would most likely look like a good connection. Pass a bit of current through it and the situation changes quickly.

    HTH
     
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  4. OHP
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    OHP

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