Where could I find a 12v output signal to signal when engine is running?

Discussion in 'Gen 2 Prius Accessories & Modifications' started by Tekdeus, Dec 7, 2016.

  1. Tekdeus

    Tekdeus Shifted to Green

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    Hello friends, I am wondering if there is somewhere from which I can trigger a relay with a 12v source just when the ICE engine is running? Thanks for your help/suggestions
     
    #1 Tekdeus, Dec 7, 2016
  2. Market05

    Market05 New Member

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    Simple solution would be the accessory plug.
     
    #2 Market05, Mar 16, 2017
  3. ChapmanF

    ChapmanF Senior Member

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    The accessory plug is powered any time the car is in ACC, ON, or READY ... not just when the engine is running, as the question asked.

    There's probably no one more likely to have found a good circuit for that than hobbit.

    -Chap
     
    #3 ChapmanF, Mar 16, 2017
  4. Kevin_Denver

    Kevin_Denver Active Member

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    I know with a scanguage or other OBD tool, you can monitor the engine RPM. I'm sure there's a way to use a microprocessor to give a positive output signal when RPM>0.

    However, this seems overly complicated. Have you taken a close look at the Prius wiring diagram? I'd imagine there are some circuits that are only hot when the engine is on (fuel pump maybe?). Pulling 50mA from such a circuit to drive a relay shouldn't cause any problems. What do you want to do with it?
     
    #4 Kevin_Denver, Mar 22, 2017
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