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Window fuse always hot -- does that make any sense?

Discussion in 'Gen 3 Prius Main Forum' started by Johnny Cakes, Oct 28, 2019.

  1. Johnny Cakes

    Johnny Cakes Senior Member

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    Title says it all -- I needed to add a circuit so I used a tap-a-fuse and picked the rear passenger window circuit as being pretty safe in case something went wrong (as opposed to the airbag circuit!).

    As it turns out, that circuit is always hot -- ignition off or on. That makes no sense to me since obviously the windows don't work when the car is off.

    I moved the tap to a different fuse and everything is fine -- circuit off when car off -- but it made me curious. What's up with the window fuse circuit being always hot?
     
    #1 Johnny Cakes, Oct 28, 2019
  2. BZzap!

    BZzap! Senior Member

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    Check the ground circuit with an ohm meter and see if its switched instead of the +. Some circuits interupt the ground for switching.
     
    #2 BZzap!, Oct 28, 2019
    Last edited: Oct 28, 2019
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  3. frodoz737

    frodoz737 Top Wrench

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    This should answer your question.
     

    Attached Files:

    #3 frodoz737, Oct 28, 2019
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  4. Johnny Cakes

    Johnny Cakes Senior Member

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    If I read the diagram correctly, you both hit the nail on the head. The power window interrupts ground for switching. Thanks!

    In the past I recall people asking about getting constant 12v in the interior of the car and I recall the answers were rather convoluted. Apparently, its quite easy. I'll add some key words so this thread will pop-up in a future search:

    CONSTANT 12v
    CONSTANT 12 volts
    CONSTANT POWER
    12v POWER WHEN CAR OFF
    12 volt POWER WHEN CAR OFF
    FUSE HOT
     
    #4 Johnny Cakes, Oct 28, 2019
    Bay Stater, RMB, tvpierce and 1 other person like this.
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