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Problem with 2005 Prius temperature control

Discussion in 'Gen 2 Prius Main Forum' started by Vishy Visweswaran, Mar 20, 2013.

  1. Vishy Visweswaran

    Vishy Visweswaran Junior Member

    Joined:
    Jan 15, 2013
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    Location:
    Chicago region
    Vehicle:
    2005 Prius
    Model:
    N/A
    Hello everyone,

    This is my first time posting to this forum.

    I have a 2005 Prius that's got a strange temperature control problem. When the temperature is set to MAX COLD, then it blows cold air as expected. As soon as the temperature is increased slightly (say to 65 degrees) the air gets really hot - as if it is already on MAX HOT. Between 65 and MAX HOT, the air stays consistently very hot.

    I would appreciate some pointers on what to look for. If this should be posted to another forum, please direct me there.

    Thank you for any help.

    Vishy
     
    #1 Vishy Visweswaran, Mar 20, 2013
    PriusCamper likes this.
  2. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

    Joined:
    Sep 10, 2012
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    Location:
    Harrison Township, Michigan
    Vehicle:
    2015 Prius
    Model:
    Four
    Myself and another Priuschatter were JUST discussing this in another thread. We experience the same exact thing and its annoying.

    Ill subscribe to this thread to check for any resolve.
     
    #2 PriusGuy32, Mar 20, 2013
  3. nh7o

    nh7o Off grid since 1980

    Joined:
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    Location:
    Hawaii
    Vehicle:
    2009 Prius
    Model:
    II
    Here are the A/C service manual's suggestions:

    Temperature Control: No temperature control (only Max. cool or Max. warm)
    Suspected area:
    1. Steering wheel pad switch circuit
    2. Air mix damper control servo motor circuit
    3. Air mix damper position sensor circuit
    4. Air conditioning amplifier

    The first relates to the scroll cable inside the steering wheel, which have been know to fail occasionally. 2 and 3 relate to the position of the air mix damper, which can be heard moving (a creaking sound in the dash). 4 just says maybe the A/C ECU is bad, and could be replaced with a salvage unit more than likely. All these would require some time tracing wires, so probably the only way to proceed is to get the A/C service manual, a voltmeter, and have a look. There is a possibility that there are DTC set if any of the sensors are not working, so getting a scan would be wise before starting. The mini VCI on eBay is the one to use. Not sure if Torque or ScanGauge will read those DTC.
     
    #3 nh7o, Mar 22, 2013
  4. Vishy Visweswaran

    Vishy Visweswaran Junior Member

    Joined:
    Jan 15, 2013
    2
    1
    0
    Location:
    Chicago region
    Vehicle:
    2005 Prius
    Model:
    N/A
    Thank you for your suggestions. I will try them out in that order and see if they do the trick.
    Vishy
     
    #4 Vishy Visweswaran, Mar 25, 2013
  5. PriusGuy32

    PriusGuy32 Prius Driver Extraordinaire

    Joined:
    Sep 10, 2012
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    Location:
    Harrison Township, Michigan
    Vehicle:
    2015 Prius
    Model:
    Four
    When I had my Techstream hooked up to my Prius last week, I found some interesting settings in the HVAC menus but was afraid to mess with them.

    Is there some kind of adjustment that can be made through Techstream?
     
    #5 PriusGuy32, Mar 25, 2013
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