Climate Control - Auto - AC always on

Discussion in 'Prius v Main Forum' started by touch_em_all_joe, Mar 13, 2012.

  1. touch_em_all_joe

    touch_em_all_joe New Member

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    I am wondering why the AC always seems to be turned on when you set climate control to auto. I see this making sense in the summer, but in the winter it seems strange.

    Are there any issue with leaving this on as the auto seems to want to do? Does it do anything when it is cold outside (and windows don't seem to be fogging up)?
     
  2. jdcollins5

    jdcollins5 Senior Member

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    I do not see an issue with leaving the AC on in Auto, even though I turn mine off in cold weather.

    As long as the cabin temp is lower than your temp setting the system is going to call for heat and not AC. Only if the cabin temp gets above your temp setting will the system call for AC.

    If you call for defrost the system will use AC for humidity control whether the AC light is on or not.

    In spring and fall moderate temps I like to use outside vent air and not AC to cool the cabin so I leave the AC off but the system in Auto and then adjust the temp up or down to get the air flow from the face vents and the fan speed where I want it.
     
  3. babybird

    babybird Member

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    I deliver pizza in my Prius, and I normally turn it off in the winter unless the windows start to fog up, but I have also experimented a few weeks with leaving it on, and have found that if it's cold out and the humidity sensor isn't saying the windows are fogging up, it barely ever runs the compressor. It seems to start it up at very low speed now and then for a few seconds, probably just to lubricate it, but there was no detectable mileage difference and very little noticeable difference in HV drain while sitting. Now I mostly only turn it off when it's a little warmer out and just don't want to use it.
     
  4. Tideland Prius

    Tideland Prius Moderator of the North
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    Even in -40, the A/C light is on


    [​IMG]


    If you're in AUTO mode and the A/C light is on, it doesn't mean that the A/C compressor is running. It just means that the climate control will cycle the compressor as necessary (dehumidify or cool the cabin depending on season). If you're in AUTO and the A/C light is off, then the climate control will not use the A/C compressor.

    If you want to force the A/C compressor to run, get out of AUTO mode and keep the A/C light on. Then your compressor will be running.
     
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