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2005 Air Conditioner Resets Constantly to 75 degrees

Discussion in 'Gen 2 Prius Main Forum' started by wpaxt, Aug 23, 2013.

  1. wpaxt

    wpaxt Junior Member

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    My 2005 Prius, 88K miles, has developed an odd quirk. For about a month, the AC will not retain the last temperature setting. For example, you drive the car, set the temperature to max cold, arrive at your destination, turn the car off and when you start it again the temperature has reset to 75 degrees. Never used to do this before. Any thoughts? I'm hoping it is just a module of some sort and not a major AC repair.

    Thanks for the help.

    Bill in Los Angeles
     
    #1 wpaxt, Aug 23, 2013
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Bill,

    I understand that your normal practice is to leave the temp at MAX COLD and that until recently, the setting would remain there. If my understanding is correct, a few comments:

    1. The A/C amplifier is probably causing this change in behavior. Replacing that amplifier with a new part is not a minor repair though so if this is the only concern you may want to live with the problem for a while.
    2. I am wondering why you want to leave the temp at MAX COLD since that forces the AC compressor to run at all times, thus negatively impacting mpg.
    3. As an alternative to that, I suggest using the AUTO AC function and setting the temperature to a comfortable level. Then the AC compressor will cycle on and off as needed to maintain that temperature.
     
    #2 Patrick Wong, Aug 23, 2013
  3. wpaxt

    wpaxt Junior Member

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    Patrick,

    Thank you for your prompt & informative reply. Good advice. The car is my wife's & she insists on MAX COLD despite my advice to the contrary. I will suggest to her to try the AUTO AC function & see if that helps. And we will see if she can live with the change in behavior in lieu of replacing the A/C amplifier.

    Thanks again for the help.

    Bill
     
    #3 wpaxt, Aug 23, 2013
  4. nh7o

    nh7o Off grid since 1980

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    Is your wife perhaps over 50 years old? If so, then the situation is understandable.:rolleyes:

    That said, outside of just short trips, max cold in my car would be intolerably cold, so maybe the system is not working up to its best ability.
     
    #4 nh7o, Aug 23, 2013
  5. wpaxt

    wpaxt Junior Member

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    You know, that is really funny because she is!
     
    #5 wpaxt, Aug 23, 2013
  6. TheEnglishman

    TheEnglishman Member

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    I set my A/C to 76 degrees on AUTO most of the time. It's very comfortable to me. 70 and below would make me freeze.
     
    #6 TheEnglishman, Aug 25, 2013
  7. BFAyer

    BFAyer Junior Member

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    My 2008 did this when the 12 volt battery was going bad. Since I replaced the battery it has not happened again.
     
    #7 BFAyer, Aug 26, 2013
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