Hyundai Sonata Windows Fogging

thuxthux Member Posts: 1
edited October 2014 in Hyundai
I just bought a 2007 Sonata. I love it so far. However, on the way to work this morning, my windows were really, really fogged up. Even with the defrost pumping full blast, the back windows remained fogged. Is this a known problem? Thanks.


  • ray_h1ray_h1 Member Posts: 1,134
    Which trim level Sonata? The "GLS" and "SE" trim level Sonatas have a manually controlled heating/air conditioning system. In those, pressing the button for the AC compressor will clear the window fogging, though you might have to adjust the heat control knob to a warmer setting to keep the chill off. In the "Limited"'s trim level, cycling the AC compressor occurs automatically since those models have automatic climate control. It's possible your in-glass defroster in the rear glass is defective or isn't connected properly to its switch (Hey, some happy-merry worker who got especially happy-merry the previous Sunday night on some 100 proof Andong soju might've missed a step when your car came sailing down the production line... ;)). It's also possible you pressed the windshield defroster switch ("curved" top and bottom shaped icon which delivers warmed air to the windshield) instead of the rear window defroster switch ("straight" top and bottom shaped icon which acivates the in-glass defroster grid in the rear glass).
  • hotrod54hotrod54 Member Posts: 82
    it's also possible you are have the vent system set to recirculate....never never never never use recirculate with heat. :D
  • xj220xj220 Member Posts: 78
    When I test drove it, it fogged up really fast. I've never seen windows fog up that quickly before and it wasn't even that cold out. I don't know what the salesperson did but I'm sure it had to do with the air/heat circulation. It never happend after that.
  • dadof6dadof6 Member Posts: 61
    The a/c compressor runs in both defroster modes on my '07 GLS. FYI
  • bhmr59bhmr59 Member Posts: 1,601
    What do yo mean by "both defroster modes?"
  • dadof6dadof6 Member Posts: 61
    1st defroster mode-the feet/window setting. 2nd is
    the full window setting on the heater control dial. Does this help?
  • ray_h1ray_h1 Member Posts: 1,134
    )) "The a/c compressor runs in both defroster modes on my '07 GLS. FYI" ((

    Then for whatever reason, excessively humid air is being processed. If you're operating the system with fresh air entry, reset the controls to "recirculate" mode. If you're already doing that, then it's time for a trip to the dealer to find and correct an extraneous air or (shudder!) coolant leak into the heater core casing. Check the drain hose from the heater core casing underneath the car - if it's plugged, condensation won't drain and you'll also end up with fogged windows regardless how you manipulate the HVAC controls. FYI
  • bhmr59bhmr59 Member Posts: 1,601
    One other thought. I really need to climb in back and clean the inside of the rear window. "Normally" it's OK. But on a damp or rainy day it appears quite fogged unless/until I turn on the rear window defroster.

    A good "windex" of all interior glass may do the trick--or not. Even though your car is new, it may have "stuff" (a film) on the glass.
  • dave868dave868 Member Posts: 64
    I really dont understand... I have 3 cars in my driveway... and when I go out every morning the heaviest fog is on my Sonata. About half the time the other 2 cars windows are perfectly clear... but the Sonata's are always wet and foggy.

    How can this be?
  • craigbrookscraigbrooks Member Posts: 420
    You don't have rain water leaking into the trunk/spare tire area do you? Moisture trapped somewhere in the car can case this.

    It's a 6 cyl curse should have bought the 4. :D
  • dave868dave868 Member Posts: 64
    I only have had the car for 2 weeks now... and it really hasnt rained. I have also noticed that the rear defogger is very weak.

    I was planning to buy the 4cyl...... until I test drove it. It was just too underpowered.
  • molina99molina99 Member Posts: 1
    I have a sonata 2009 always during damp weather (summer or winter) or in the morning both lateral windows get condensations and fog blocking my rear vision in my lateral mirrors. It tried air conditioning, using fresh air and also recycled air without any success. The only thing that works is if I pump the heater to the max but if the weather outside is 85 degrees you feel like you are in an oven.
    What do you think the problem might be?
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