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AC button not turning on

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by Juwan, Dec 16, 2020.

  1. Juwan

    Juwan Junior Member

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    2010 Prius
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    III
    AC issue only started to happen recently after my 12v battery disconnected. My fan blows fine and will turn on when I hit auto but no cold air and the AC light will not turn on. However, when I turn on the defrosters they will blow cold air with no problems. All the other lights on the dash work properly and my buttons don't seem to be sticky as some people I've seen on other forums had issues with. I assume it is possible that my AC button just doesn't work for whatever reason. If my air conditioner blows cold. I did some digging and the only forum that had similar issue was resolved by sticky off button but my off button works fine to cut off the fan. I'm hoping it's a simple fix. Thanks in advance! This is my first post but I've used Priuschat forums a lot over the past 6 months or so of owning my car including replacing the HV battery.

    Posted via the PriusChat mobile app.
     
    #1 Juwan, Dec 16, 2020
  2. Juwan

    Juwan Junior Member

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    III
    I don't know if this helps but I live in Hawaii and usually have my AC on at low speed and haven't ever used heat. I don't know anything about fuses but I'm willing to give it a go if I feel like I can do it. Worst comes to worst I will take it into a mechanic and have him diagnose it in a week or so as its winter and it's not as hot.

    Posted via the PriusChat mobile app.
     
    #2 Juwan, Dec 16, 2020
  3. rjparker

    rjparker Tu Humilde Sirviente

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    If you are sure its cooling in defrost it could be the control. Someone with a Toyota scanner may be able to monitor the status of the control. The ac compressor is high voltage three phase from the inverter. Don't expect just any ac shop to have good experience with this system.
     
    #3 rjparker, Dec 16, 2020
  4. tankyuong

    tankyuong Senior Member

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    Check the 12v battery
     
    #4 tankyuong, Dec 16, 2020
  5. AzWxGuy

    AzWxGuy Weather Guy

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    You might want to try this HVAC chicken dance to rule out other contributors (such as a weak 12 V battery).

    The keystrokes for this test are start from ACC mode (power on without brake), hold down AUTO and Recirculate/Fresh Air buttons, and press START again. Should see A/C LCD and all LED lights blink 4 times at 1 second interval followed by a code displayed where the preset temperature (digits on left side of LCD) are normally displayed. A 00 code means no problems. Then press OFF to escape.

    If you see a code, you'll need the maintenance manual to decipher what it is. You should be able to locate that with a suitable thread search, or maybe someone else will chime in with an attachment.
     
    #5 AzWxGuy, Dec 17, 2020
  6. Garo Barsemian

    Garo Barsemian New Member

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    Did you ever figure this one out? I’m having the same issue.
     
    #6 Garo Barsemian, Aug 4, 2022
  7. ChapmanF

    ChapmanF Senior Member

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    Agreed, if the A/C will work in defog mode, and the A/C green light works during the self test, and you can't make the green light turn on and off by pressing the A/C button (while the blower is on), then the button is a suspect and there aren't many others.
     
    #7 ChapmanF, Aug 4, 2022
    seaglasspearl2013 likes this.
  8. Cortega315

    Cortega315 New Member

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    Did anyone figure this out? I just replaced my 12v battery and now my AC button won’t turn on anymore. The ac was working perfectly until the battery was replaced.
     
    #8 Cortega315, May 1, 2024
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