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Does AC turn on automatically in split windshield /floor mode?

Discussion in 'Prius v Main Forum' started by iamajai, Oct 31, 2014.

  1. iamajai

    iamajai New Member

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    We have a 2013 Prius V and I would like to find out if AC is always on while in split windshield/floor mode for the ventilation system? We have the AC turned off most of the time and when you switch the vent mode to split windshield/floor the little AC button light does not come on, but does that mean it is truly off? Every other car I've driven turns on AC in the vent position.

    Hoping we aren't inadvertently harming our gas mileage by leaving the system in that vent position.

    Thanks.
     
  2. rdgrimes

    rdgrimes Senior Member

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    1) Use of the A/C does not "harm" your mileage. It may reduce MPG slightly when its working extra hard.
    2) Why not just leave it in auto mode? In any case the A/C compressor is only running when the light is on.
    Are you confusing "bi-level" ventilation with the floor-defrost option?
     
  3. JimboPalmer

    JimboPalmer Tsar of all the Rushers

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    Anytime the defrost symbol is in the mode you choose, the A/C is dehumidifying the air.

    And yes, this is a good thing.
     
  4. bisco

    bisco cookie crumbler

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    i would like a definitive answer to this as well. when i turn on split mode, i can't hear any a/c compressor noise unless i hit the button.
     
  5. iamajai

    iamajai New Member

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    1) I would think operating the AC compressor lowers mileage. It is an additional load on the vehicle (electrically driven if I understand correctly).
    2) I like to leave the ventilation split between windshield(defrost) and floor for most of the winter. Helps keep the windshield clear even if the AC doesn't run.

    If the AC is not on when the little AC light is off then that is great. It is just that my experience in other vehicles has been that AC is on whenever you are defrost (even split with floor) and there is usually no way to turn it off.

    I suppose one could press the AC button and listen from outside the car for a change in sound to test it.
     
  6. Mendel Leisk

    Mendel Leisk Senior Member

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    My AC does not run if I haven't pressed the AC button. Even pressing Auto. The AC button is a dedicated, final word on/off button, which is pretty much the way I like it. From what I've heard here, in other parts of the world the behaviour might be different, ie: if you hit Auto it may start running AC if it see's fit.
     
  7. bisco

    bisco cookie crumbler

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    i wonder if scan gauge monitors?
     
  8. Mendel Leisk

    Mendel Leisk Senior Member

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    Yeah, I've just added (XGauge) ACw (Air Conditioning watts). Was running AC last night, watched the number jump between 0 (off), 200, 250, typically. Used Front Windshield Defog one time and it jumped higher, 350 I believe. I'll check next time we're driving, do Auto, and expressly switch off AC button, and see what happens. Have a very strong hunch it'll just be zero though, I can tell by the feel of the air when AC's on.
     
  9. bisco

    bisco cookie crumbler

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    cool! can you do manual as well? just fan and split air setting, temp 'lo', thanks!
     
  10. rdgrimes

    rdgrimes Senior Member

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    The A/C compressor is a variable speed motor. At its lower speeds it can run a VERY long time without impacting SOC measurably. The blower uses as much current as the compressor does at low speeds. Even then, the compressor only runs part of the time. Its really a non factor unless its 90' out and the system is running with 3-4 bars on the blower gauge.

    You have a button for clearing condensation which is VERY effective, and this does engage the A/C. IMHO, you're over-thinking this. Just leave the system in auto mode and hit the defog button if its needed. The only time this might not be adequate is when its raining/snowing outside. 99% of the time the auto system is smarter than the average driver. Auto also keeps the A/C in standby mode, allowing it to kick in if humidity is too high.

    FWIW, depending on which model you have there may also be heated mirrors which are tied into the rear defogger. These are also quite effective for drying off the mirrors.
     
  11. drysider

    drysider Active Member

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    The answer is yes, the A/C will run in the split/defrost mode...and no, the light does not come on. There is a split mode where the defrost is not engaged and the A/C is not on. The effect on the car's mileage is probably pretty minimal.
     
  12. bisco

    bisco cookie crumbler

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    links please.
     
  13. iamajai

    iamajai New Member

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    Thanks for the responses so far. I'm encouraged to hear the AC compressor is a small draw.

    There appears to be differing opinion on the state of AC still. Would be great if the AC button was a final arbiter. Hope Mendel can come through with some testing.
     
  14. drysider

    drysider Active Member

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    I have not found it documented anywhere. I confirmed the A/C operation by watching the battery amp draw with the defrost off and on. The compressor comes on with the defrost, but the A/C light does not.
     
  15. bisco

    bisco cookie crumbler

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    thanks, and this is in manual mode and split floor/windscreen air flow?
     
  16. drysider

    drysider Active Member

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    Yes. I do not use Auto.
     
  17. bisco

    bisco cookie crumbler

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    i always felt like the air was cooler on that setting, but i figured it was my imagination.:cool:
     
  18. Mendel Leisk

    Mendel Leisk Senior Member

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    I'll check with XGauge ACw ASAP, but I'm absolutely certain, from all the AC "signs": if you've got AC off (light off on AC button), and set vent mode to this:

    Capture.JPG

    AC does not come on.

    As far as I can tell, the only time AC comes on without AC button being lit, is if you hit the front windshield defog button:

    Capture.JPG

    And then, the light on the AC button will come on, for the duration of the above button being depressed. That light will go off again, when you again depress the above button, to shut off front windshield defog.

    That's actually optimal, I wouldn't have it any other way.
     
    #18 Mendel Leisk, Nov 1, 2014
    Last edited: Nov 1, 2014
  19. iamajai

    iamajai New Member

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    Thanks for the clear explanation Mendel. If that is the case it is ideal.


    iPad ?
     
  20. bisco

    bisco cookie crumbler

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    i wonder why drysider is getting increased amperage draw?