Why do windows fog while heater is running?
10

Asked by LoneOak Jan 02, 2017 at 05:36 PM about the 1999 Toyota Corolla LE

Question type: Maintenance & Repair

On My Mothers 1999 Toyota Corolla when she runs the heater the windows fog
up in the car.  If she runs the AC at the same time it clears up the windows.  We
don't live close by so I hope to be able to find out whats wrong so I can get
parts and plan the repair the next time I visit.  Thanks for any help!

3 Answers
59,095

enginecreator answered 7 years ago

Its most likely normal. Turning on the a/c introduces outside air into the mix and takes out some of the humidity. Its physics, humidity, biometric pressure, it can happen to either inside or outside glass depending on circumstances. If it does it while heat is on open a window slightly. If its moisture in system from leak in heater core replace it, you will know if that is the issue because of the coolant smell in cabin.

Mark helpful

F_O_R answered 7 years ago

The AC condenses moisture out of the air which reduces the humidity and fogging.

Mark helpful
10

LoneOak answered 7 years ago

I told her to let me know if she smelled antifreeze or saw any in the floor. For some reason my Mom won't let me fix anything of hers unless I just do it, She never tells me when something is wrong. Thanks for the help guys, got to keep her informed so she will keep feeding me the symptoms! Any more ideas will be appreciated.

1 people found this helpful.
Mark helpful

Your Answer:

Related Questions

  • Why do windows fog while heater is running? 3 Answers

    On My Mothers 1999 Toyota Corolla when she runs the heater the windows fog up in the car. If she runs the AC at the same time it clears up the windows. We don't live close by so I hope to be able ...

    1999 Toyota Corolla LE

    -

    Maintenance & Repair

  • Why is my car running weird? 3 Answers

    I had to remove the battery to install the drivers side headlights, and after I was done and put the battery back in, the car feels like it has very low power in the engine when it is running. I'm...

    2005 Toyota Corolla CE

    -

    Maintenance & Repair

  • Why do I not have running nor instrument panel lights? 1 Answer

    It was raining one day, and my instrument panel lights started flickering on and off, I tapped above the panel, and they stayed on. Same story, different night; only this time, they flickered on and...

    2008 Toyota Corolla S

    -

    Maintenance & Repair

  • Brake lights are always on while the car is running - 1990 Toyota Corolla 2 Answers

    1990 Toyota Corolla Station Wagon When I start my car, all 3 brake lights come on and stay on the entire time the car is running. When I shut the car off, the lights go off, so I don't think it's th...

    1990 Toyota Corolla

    -

    Maintenance & Repair

  • why did my car suddenly stop running while driving? 2 Answers

    my car just suddenly stopped running while driving and will crank now but won't run long

    2000 Toyota Corolla CE

    -

    Maintenance & Repair

Corolla

Looking for a Used Corolla in your area?

CarGurus has 2,238 nationwide Corolla listings starting at $2,450.

Postal Code:

Shortcuts

Search Toyota Corolla Questions

CarGurus Experts

  • #1
    Jeff Polhemus
    Reputation
    3,360
  • #2
    Gene Arnett
    Reputation
    3,270
  • #3
    hashimmir
    Reputation
    2,500
View All

Find great deals from top-rated dealers

Search

Related Models For Sale

Used Toyota Camry
53 Great Deals out of 1,003 listings starting at $3,995
Used Honda Civic
195 Great Deals out of 3,923 listings starting at $1,130
Used Honda Accord
41 Great Deals out of 980 listings starting at $2,995
Used Toyota RAV4
120 Great Deals out of 3,000 listings starting at $6,012
Used Toyota Tacoma
46 Great Deals out of 861 listings starting at $9,975
Used Hyundai Elantra
148 Great Deals out of 3,050 listings starting at $1,995
Used Honda CR-V
156 Great Deals out of 4,779 listings starting at $100
Used Nissan Sentra
66 Great Deals out of 2,149 listings starting at $1,800
Used Toyota Yaris
13 Great Deals out of 209 listings starting at $2,795

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use. Content will be removed if CarGurus becomes aware that it violates our policies.