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Intermittant AC Problem

Discussion in 'Gen 2 Prius Technical Discussion' started by dwgsp, May 25, 2012.

  1. dwgsp

    dwgsp Junior Member

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    Started having an Intermittant problem today with my '07 Prius that I have owned for about a month. It was a warm day in the high 80's, so I had the AC on as i ran errands. I stopped atsandy ore, and was inside for a couple minutes. When I came back and started the car, the AC and blower were both nonfunctional. I played around with the touch panel controls, but could not get them to work.

    So I went on to my next stop, and the same thing happened. But this time I noticed that the gas engine did not start right away - it waited until the car started moving a ways before it (the engine) came on. I then pulled over and played with the controls some more, and apparently did something right because the AC and blower came on and worked fine until my next stop.

    Now I come back out and start the car, and the same thing happens again. Again I pull off after the engine finally starts, and again get the AC and blower to work after playing with the controls. I drive home, and park in the garage.

    A couple hours later, I need to run another errand, and this time everything works fine. So it seems that I have an Intermittant problem, perhaps related to engine or compressor temperature in some way. Does anyone have any ideas what might be happening and how I might fix it?
     
    #1 dwgsp, May 25, 2012
  2. Ophbalance

    Ophbalance Member

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    I could be wrong, but I *think* when problems like this have been mentioned in the past it's due to the inverter running too hot. You might want to try and search on that.
     
    #2 Ophbalance, May 26, 2012
  3. nh7o

    nh7o Off grid since 1980

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    Take a look in the inverter coolant reservoir while the car is in ready mode, and make sure you see turbulence on the surface of the liquid. If not, then your coolant pump is not working. There are some videos and plenty of posts here about replacing that part.
     
    #3 nh7o, May 26, 2012
  4. dwgsp

    dwgsp Junior Member

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    Ok, there is turbulence in the inverter coolant reservoir, so I guess that the pump is ok.

    I'll add that the problem occurred again today, and instead of messing with the controls I drove the car onto the highway, and after about a minute at highway speed the blower came on and the AC worked. So it does look like something's getting too hot. Does the blower motor have cut off when it gets too hot?
     
    #4 dwgsp, May 26, 2012
  5. nh7o

    nh7o Off grid since 1980

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    Some ideas: radiator(s) clogged with debris, radiator fans not coming on when needed, or check the sight gauge on the A/C and see what it tells you about the refrigerant level (some recent posts about that.) Low levels can cause intermittent activity.

    Note that the car will pull away from a stop without starting the engine if the battery is full enough, and the accel pedal is not pushed too far, so that part is normal. In fact, it's a feature :)
     
    #5 nh7o, May 26, 2012
  6. Frayadjacent

    Frayadjacent Resident Conservative

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    A problem with inverter temperature would manifest itself in the ! warning light and Check Engine light coming on.

    When my inverter cooling pump went tits-up last August, I got the ! light and CEL, but everything was working fine. I stopped in a parking lot and powered off and checked under the hood. Everything looked fine. When I powered on, the blower was working, but the AC compressor was not coming on (blowing warm air).

    I'm hesitant to say that the situation dwgsp is in is the inverter.

    My guesses from here would be:
    - Low refrigerant pressure
    - 12v aux battery problems
    - some other electrical problem resulting in the AC system not turning on properly.


    What does the MFD show under the Climate screen? Does it show off when it should be on, or does it show that it's on when it's not?
     
    #6 Frayadjacent, May 27, 2012
  7. koolingit

    koolingit Member

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    #7 koolingit, May 27, 2012
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