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Dome Light Wire

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by Flengineer, Jun 20, 2019.

  1. Flengineer

    Flengineer New Member

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    2012 Prius v three

    Does anyone have a wiring diagram, specifically wire harness routing for the dome light? I'm adding some LED lights to the floor and need to tap the dome light circuit but I don't want to run a wire all the way up to the dome light. I only need 1mA max when the door opens or when I approach the car.

    I think it may be in the panel to the rear of the driver's side door but I don't want to pull the panel off if it's not in there.
     
    #1 Flengineer, Jun 20, 2019
  2. Air_Boss

    Air_Boss Senior Member

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    It's a three conductor ribbon that runs up the A-pillar to, then back to the dome light, from the map light cluster.
     
    #2 Air_Boss, Jun 20, 2019
  3. rjparker

    rjparker Tu Humilde Sirviente

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    The map light control is ground true when on. There is a UL1 connector way under the dash but it might be easier to run a wire from the map light itself. Again there is no 12v that energizes, 12v is up there constant with a body ecu pulling the light circuit low when on. This image is from a pdf I posted on how to add a homelink mirror which needed power. Be careful when adding something to this solid state sink as a miss-wire could damage the ecu.

    A7800436-6A01-4E8A-B55F-3784A9EF504B.jpeg
     
    #3 rjparker, Jun 20, 2019
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  4. Flengineer

    Flengineer New Member

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    Which pillar, in front or behind the driver's door or passenger's door?
     
    #4 Flengineer, Jun 20, 2019
  5. Flengineer

    Flengineer New Member

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    So pin 15 is ground when the door opens? Even better! I just need a TTL signal so a couple resistors and a 4.7V zener should protect the ecu. If I have to I will run the wire up to the map light but I'm hoping I can find down lower.
     
    #5 Flengineer, Jun 20, 2019
  6. Air_Boss

    Air_Boss Senior Member

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    A-pillar is between windshield and front door glass.

    B-Pillar is between front and rear door glass.
     
    #6 Air_Boss, Jun 20, 2019
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  7. Flengineer

    Flengineer New Member

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    Good to know, thank you Boss!

    @rjparker I assume the pdf you linked is from a service manual, is that something the public can buy? If so where would I find it?
     
    #7 Flengineer, Jun 20, 2019
  8. rjparker

    rjparker Tu Humilde Sirviente

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    The pdf Is one I put together that includes some service info. Look for it several years ago. There is no actual service manual, instead you have to subscribe to Toyota Information System online. Then navigate around the system which takes a little skill. You can download pieces at a time, not the whole thing.

    Toyota - New Subscription
     

    Attached Files:

    #8 rjparker, Jun 20, 2019
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  9. Flengineer

    Flengineer New Member

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    Ahh ok, thank you for the info and for your work.
     
    #9 Flengineer, Jun 21, 2019
  10. rjparker

    rjparker Tu Humilde Sirviente

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    No. Check the drawing again.
     
    #10 rjparker, Jun 21, 2019
  11. Flengineer

    Flengineer New Member

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    Pin 15 on UL1, Pin 6 on the Map Light board.

    I will probably use Pin 7 on the Map Light board so that the switch will activate my circuit. I will verify before connecting anything.

    Doorlight.JPG
     
    #11 Flengineer, Jun 21, 2019
  12. Flengineer

    Flengineer New Member

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    So, I have replaced the dome lights with LEDs and the ECU isn't behaving as I expected it to. Since I don't have a whole lot of info on the ECU I did some experimentation and came up with this circuit. It works and the resistance values are high enough that it shouldn't cause any issues. I also moved to the Room Light Assembly because it was easier to run the wire there.

    Doorlight.JPG
     
    #12 Flengineer, Jun 24, 2019
  13. Flengineer

    Flengineer New Member

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    Just an update for others who might need the info.

    So the circuit above works but the dome LEDs stay very dim when they are supposed to be off. The floating ground from the ECU isn't going to work for me. My last resort which will definitely work is using a hall effect sensor to measure the current on one of the lights.

    The sensor is an ACS712 for Arduino.
     
    #13 Flengineer, Jun 26, 2019
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