AC comes on then turns to heat

Discussion in 'Gen 2 Prius Technical Discussion' started by Avestor, Apr 25, 2020.

  1. Avestor

    Avestor Junior Member

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    2005 Prius with AC problem. When car is started AC will come on and cool for about 5 minutes. Then Air turns hot. Thoughts on issue? If cooling at all it must have a charge and compressor must work ???
     
  2. SFO

    SFO Senior Member

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    Welcome to PriusChat!!

    Do you have any warning lights on the dash?

    What is the mileage, and overall vehicle maintenance history like?

    You can view prior dealer only maintenance by entering the VIN at : https://toyota.com/owners
     
  3. valde3

    valde3 Senior Member

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    Incorrect charge could cause this. But so other things. But as it cools and you don't have fault light it's probably not a bad compressor. Unfortunately this is almost impossible to diagnose without being there and/or having a gauge set or checking the system fill.
     
    #3 valde3, Apr 26, 2020
    Last edited: Apr 26, 2020
  4. Mendel Leisk

    Mendel Leisk Sand Pounder

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    This seems familiar. Big help, I know...

    Something for a few minutes, then crapping out?

    Compressor?
     
  5. Avestor

    Avestor Junior Member

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    Dealer first did an evac and recharge, but problem persisted.
    Then recommended replacing AC pressure switch (got second dealer opinion)
    Second dealer said AC pressure switch almost never goes by itself, likely compressor.
    That's where things stand.
    I love the car, but car value stands at $5,300 max so I don't want to plow thousands into it searching for the problem.
    Unfortunately failed AC makes it difficult to drive for a good portion of the year.

    yes that is it. but only when turned off for a while.
    AC works for about 5 minutes then turns to heat or outside air temp (it was summer when I was diagnosing so hard to tell)
     
    #5 Avestor, Apr 27, 2020
    Last edited by a moderator: Apr 27, 2020
  6. AzWxGuy

    AzWxGuy Weather Guy

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    How about a failing traction battery? You would know that by the discharged or erratic state of charge display on your MFD. Yes, we're just guessing. Was that a Toyota dealer you mention? They should know what to do.
     
  7. valde3

    valde3 Senior Member

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    Testing the AC pressure switch should be easy. All you would need is the AC pressure gauge and compare the stage of switch to pressure. If dealer did that and came to conclusion that switch was bad then switch is bad.
     
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