Prius Prius Prime 2019 heat problem

Discussion in 'Prime Care, Maintenance and Troubleshooting' started by syldeninf, Nov 18, 2019.

  1. syldeninf

    syldeninf New Member

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    my Prius Prime 2019 is barely heating.,if I set the vents to the foot,i can succeed to have a little heat but cold air is comming out from the front vents even if the control shows floor only.
    Any Ideas what could be the problem?


    Posted via the PriusChat mobile app.
     
  2. Flaming

    Flaming Member

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    sounds like a blend door actuator stuck or malfunctioning
     
  3. jerrymildred

    jerrymildred Senior Member

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    What's the outside air temperature? I'm not familiar with how it works in northern cold yet, but there are limits to what it can do without running the engine.

    Have you tried just setting the temperature you want with the controls on auto to see what happens?
     
  4. bisco

    bisco cookie crumbler

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    welcome!
    the vents are less important than the temp control and hv/ev. can you give us more details on those?
     
  5. sam spade 2

    sam spade 2 Senior Member

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    Good question......maybe.
    But if it is not working right, it is a WARRANTY issue and it makes little to NO difference what the cause is.
    Take it in.
     
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  6. kevins007

    kevins007 Active Member

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    The Prius won’t heat well without using the ICE if it is below 35-40 F. I live in Wisconsin and that has been my experience.
     
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  7. jerrymildred

    jerrymildred Senior Member

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    If I read between the lines correctly, I think what @syldeninf wants to know is if it's pilot error or does it need a trip to the dealer. That's probably best determined by careful reading of the owner's manual unless there's a friendly Prius owner nearby who can demonstrate it and compare behaviors.
     
  8. Salamander_King

    Salamander_King Senior Member

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    If the heating is during 100% EV at a temperature above -10C (14F) but below +4C (40F), as @kevins007 commented, PRIME is using 100 gas injected heat pump mode. While it is much more efficient in terms of energy requirement from the traction battery, my experience has been that it does not perform adequately to heat the whole cabin. I often drive my entire commute 18 miles on EV with the heat set at AUTO 70F with the ambient temperature around freezing mark 0C (32F) without cabin temperature never reaching 4C(40F) during the trip. In those days I mix HV during my drive to turn on ICE to provide more heat.
     
  9. Old Bear

    Old Bear Senior Member

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    Ah... the major short-coming of electric vehicles: they're so efficient that they don't throw off waste heat to heat the cabin like an internal combustion engine does.

    See my post from last March: Affect of Cold Weather and the Heater on EV Range | PriusChat

    Then go to Walmart and buy a propane camp heater -- just don't catch your car on fire or die of carbon monoxide poisoning. ;)

    car-heater.jpg
     
    #9 Old Bear, Nov 19, 2019
    Last edited: Nov 19, 2019
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  10. sam spade 2

    sam spade 2 Senior Member

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    I see that wink at the end.
    But some people no doubt will somehow think that is a good idea.
    IT IS NOT.
    The vehicle has a mode builtin to get good heat on cold days; JUST USE IT.

    Don't let your obsession with fuel efficiency lead you to do something stupid.
     
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  11. m8547

    m8547 Active Member

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    Here are my observations about the heat:

    The fan speed seems to vary based on what the heat pump is doing, no matter what you set the fan to manually. While the heat pump is warming up the fan speed will be lower.

    On low fan speeds it puts out a very weak amount of heat. You might not even notice it unless you know where the floor vent is. It also takes a while (sometimes 10 minutes or more in very cold weather) to start blowing hot air. But it does effectively and efficiently heat the car.

    In a recent snowstorm I had the heat blasting all the way to work and all the way home to keep the windshield from icing up. I was using the feet+windshield mode, I had the temperature set to either 76 or High, and the fan was set about 3/4 of the way up. On the way to work the temperature was probably 17 to 22F, and on the way home it started around 32 and ended around 14. The behavior of the heater was similar each way. I turned it on to let it warm up while I cleaned snow off the car. After it warmed up it blew plenty of warm air for most of the drive, but cooled off and basically stopped working towards the end of the drive. I don't know if that's because the air outside got colder, or because it had to defrost the outside coil, or something else. For example I was still getting a lot of hot air even as the temperature dropped to 17 to 18F on the was home, but it stopped working after that as the outside air got colder. It was just blowing cool air. On the way to work it never dropped below 17F, but the heat still stopped working as I got close to work.

    My commute is about 15 miles each way, and with the heat blasting the car used more than 90% of the battery each way. It was in EV mode 100% of the time.

    Edit: Edited for clarity
     
    #11 m8547, Nov 19, 2019
    Last edited: Nov 19, 2019
  12. bisco

    bisco cookie crumbler

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    the engine didn't come on at 20 below zero?
     
  13. Salamander_King

    Salamander_King Senior Member

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    How did you select that mode? On my car, if WINDOW mode is selected all the other air flow (to cabin) are disabled. I can't select feet+windshield at the same time, I don't think.

    manual window.png

    Manual AC on.png
     
  14. m8547

    m8547 Active Member

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    I think it's that first one. The down arrow means some air is blowing on your feet. The "Plus" trim has a slightly different graphic for it.
     
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  15. Salamander_King

    Salamander_King Senior Member

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    Do you mean the pic on the top, with the arrow to the window? Does that mode also send the air to the foot as well as to the window? Unfortunately, it is impossible to "feel" the air out to the windshield, but my recollection is that if I select the air flow to "WINDOW" no air is coming to my foot, but I just did not feel strong air flow, since I had it on low 2 fans setting.

    Edit: Sorry, I edited my comment after realizing you said "firs one".
     
  16. m8547

    m8547 Active Member

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    I found some interesting tidbits in the owner's manual. Here's some info about the defrost cycle:
    upload_2019-11-19_9-39-33.png

    Here are the different graphics depending on the trim level. Mode 4 has the same function either way.


    upload_2019-11-19_9-40-31.png
    upload_2019-11-19_9-44-39.png

    There was a question in another thread somewhere about what does the AC button do when it's cold out.
    upload_2019-11-19_9-41-15.png

    How to start remote AC:
    upload_2019-11-19_9-42-21.png

    I hadn't heard this before, but it makes sense. This says the power is restricted in remote AC mode. That could explain why it sometimes seems to not work, and why it sometimes takes three 10 minute cycles to melt frost off my windshield.
    upload_2019-11-19_9-43-38.png
     
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  17. m8547

    m8547 Active Member

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    When the defogger is running, you should be able to feel air coming out the small vent that points towards the side windows. In "mode 4" you should also be able to feel air coming out the floor vent if you know where to put your hand. It's a small circular vent under the dash, slightly to the right of the centerline of the steering wheel.

    upload_2019-11-19_9-51-39.png
     
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  18. jerrymildred

    jerrymildred Senior Member

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    The answer is in @m8547's detailed answer. (y)

    Just to single out and clarify this question, the answer is that the arrow isn't to the window; it's to the feet. It means windshield and feet. ;)

    Wouldn't it be nice to be able to just say, "Jarvis, I'm chilly." Or "Jarvis, can you do something about the windshield fog, hopefully without starting the engine?" Where's Tony Stark when we need him? :ROFLMAO:
     
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  19. Salamander_King

    Salamander_King Senior Member

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    Yeah, Plus trims diagram look better depict the two separate air flow. As you said, I thought the diagram on the large screen was showing the air flow only to the window, but the arrow was meant to indicate the foot air flow. Now I know. BTW, in my experience, if window defogging is not needed, air flow to the foot and face (both arrows) is the quickest to heat up the cabin temperature, not the foot only.
     
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  20. m8547

    m8547 Active Member

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    I think you can do that with a Tesla. Toyota's in car electronics are a a decade behind in comparison.
     
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