2012 Prius C Vent Blowing Hot air all the time

Discussion in 'Prius c Care, Maintenance and Troubleshooting' started by redmotomaster, Mar 20, 2018.

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  1. redmotomaster

    redmotomaster New Member

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    Hello all, this is my first post but I want to let others know my experience because I couldn't find anything online to help me with this problem. My 2012 prius C started blowing hot air from the vents and it wouldn't stop no matter what I did including turning A/C or heater on and off. I tried taking it to the local repair shop and all they did was change the refrigerant over and over. I took it to the dealership and they said it was the Heater side blower door. They came to this conclusion after replacing the compressor and the a/c side blower door. $3000 later and my problem is solved. It took them almost 2 weeks to solve this issue and they said that Toyota of america had never encountered any problem like this before.

    So if your prius starts blowing hot air for no apparent reason and won't stop, it may not be a dirty evaporator, it may be the actuator on the heater side blower door, this is important because apparently there are two vent doors and actuators on this model.     Also be aware that there is a service advisory for the A/C compressor on this model, which unfortunately I never caught because It wasn't diagnosed within 24 months of the advisory. Thanks for all the information on this site, and I hope others are more lucky than I was.
     
    #1 redmotomaster, Mar 20, 2018
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  2. bisco

    bisco cookie crumbler

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    any idea why a stuck blower door would let heat in if you have the temp set to 'min'?
    i thought they just changed air flow direction. it seems to me that the problem would be the valve that allows hot water into the heater radiator core.
     
    #2 bisco, Mar 20, 2018
  3. redmotomaster

    redmotomaster New Member

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    Hi thanks for the reply. I'm not sure why it was causing the problem but apparently it was confusing the entire system. The part that was replaced was 87106-52140 Servo Sub Assembly, also described as a blend door actuator. They did find the compressor was faulty as well but wasn't throwing up any codes so they replaced 88370-52012 compressor assembly. Apparently they had to consult a retired Toyota tech who had literally 20 years experience with these systems. The thing that confused me so much with this was that the old compressor actually worked to some degree when the ICE engine wasn't running, but as soon as the ICE kicked in or the car accelerated, it was like a hot hurricane right to your face making the car undriveable or very uncomfortable, especially here in Florida.
     
    #3 redmotomaster, Mar 20, 2018
  4. BeRAD

    BeRAD Junior Member

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    Three
    Hello everyone. I am having the same exact issue. I have searched everywhere and this is the only thread that I have came across. My 2013 Prius C basically has the same exact issue. When the vehicle is moving in EV mode and/or at speeds no greater than a few miles per hour, I can feel COLD air from the A/C. As I accelerate and drive any faster, I only feel HOT air (whether the temperature is set at it's lowest or highest setting, with or without the AC on or off, and/or on auto). I had the refrigerant re-filled or topped off and tested. I was advised that the compressor works fine and the problem is due to a faulty blend door actuator that will cost $2000-3000 to replace. A $130 part plus time a labor just to disassemble the dashboard?

    Does anyone know where the location of the blend door actuator and/or of any DIY tutorials/links? I've googled, searched, and youtube'd everywhere and found nothing. The closest thing I found was this youtube video (also posted on these forums):

    Removing the A/C blend door actuator | PriusChat

    Would this 2006 Gen 2 apply to a 2013 prius C as well?

    Thanks for any help!
     
    #4 BeRAD, Dec 4, 2018
  5. StockLX

    StockLX Junior Member

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    Hey BeRAD, I know this post is ancient, but did you ever find any more info on this topic or get your problem resolved? was it the blend door?
     
    #5 StockLX, Aug 3, 2023
  6. ChapmanF

    ChapmanF Senior Member

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    I did know some older cars where the heat was controlled by a valve on the coolant pipe, but in most cars these days and certainly the Prius, that isn't done. The hot coolant flows through the heater core at all times, and there is an extra door in the heater—the "blend" door or "air mix" door—that sends the air through the hot core, or bypassed around the hot core, or a mix of both.

    The advantage is when that door moves, you feel the difference in air temperature immediately. In the old cars with the coolant valve, you'd be sitting there waiting for the heater core to heat up or cool down.

    There are three different doors in a Prius heater (unless you've got one of the fancy ones with dual zones).

    The air inlet door selects whether you're getting fresh air or recirculating cabin air.

    The air outlet door selects which vents the air is coming out of.

    And the blend door, or air mix door, determines how hot that air is going to be.
     
    #6 ChapmanF, Aug 3, 2023
  7. Sonic_TH

    Sonic_TH Active Member

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    Try disconnecting the 12v battery for a few minutes. The same thing happened to mine and the only solution i found was to disconnect the 12v battery for a few minutes. I don't use heat because of that issue, but where i live is too hot, if i could eliminate heat from the A/C i would, needless and just more complication.
     
    #7 Sonic_TH, Aug 4, 2023
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