Fogging glass, automatically switches recirculation

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by ToyotaCoyotta, Jul 23, 2025 at 4:20 PM.

  1. ToyotaCoyotta

    ToyotaCoyotta Junior Member

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    2009 Prius
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    III
    My 2009 158k kilometerstand prius recently started acting weird

    The outside of the main(front glass) gets a little foggy in the down area where is ventiliation for defrost, it then takes me to use the windshield wipers to clean the fog.


    It wasnt like this before and I also noticed that the car sometimes automatically switches to inside air recirculation and not taking fresh air from outside, even though the climate control system is never on auto, why it changes automatically then ?
     
  2. BiomedO1

    BiomedO1 Senior Member

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    LE
    If the windscreen wipers takes care of it; the fog is on the outside of the glass - NOT the inside....... Your probably missing the hood gasket along the wiper cowl. Hot air from your engine compartment is blowing onto your windscreen - the differential temperatures and humidity is causing the fog up.
     
  3. CR94

    CR94 Senior Member

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    Cold (air conditioned, with compressor running) air coming out the defog outlets during mild or warm humid weather will cause the outside of the glass to fog. I've seen it happen on a friend's car, caused by operator malfunction, in his case.
     
    Brian1954 likes this.