Never had this before in my windshield when I press the windshield button. I dont know if the whether will do this but its humid today. hot and wet.

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It's likely condensation on the outside of the glass. This occurs more often in other parts of the country where the atmospheric humidity is higher on a normal basis. A writer on Edmunds, which is located in California, made a blog post about this phenomena a couple of years ago. This struck some of the blog's readers to wonder what made this a big deal. Apparently, due to the climate, people in California usually don't encounter temperature differentials (the inside of the vehicle versus the outside atmosphere) which involve higher atmospheric humidity levels.

This is condensation being formed on the outside of the glass. The cold air inside the vehicle is cooling down the glass. The outside air is hot and humid. When the hot and humid air comes in contact with the cold glass, it causes the water vapor (gas) in the air to cool to water (liquid).

 

is there any way to prevent this from happening? How do I make it go away when the windshield vent is open? The only way it goes away is when I disable the windshield vent.

 

This happens like everyday in Florida lol. That's why it doesn't strike me as abnormal. As for preventing, there's nothing really that can be done but closing the vent. Unless you can alter the natural laws of condensation.

 

Is it on the inside, wouldn’t putting on the A/C get rid of it,

 

Same here in VA. I see it alot especially with the current bout of high humanity.

 

This is normal condensation in high himidity areas... like here is Humi.. err, Houston. We get days when it's 100 degrees and a pop up shower hits you.. the steam rises up from the hot pavement.. 100% humidity after the cloud passes and the windows will fog up.

I thought most cars just don't blow A/C on the windshields for this very reason. I guess I have lots to learn about a Lexus

 

Most new vehicles automatically run the air conditioner when the defog/defrost setting is used. This is done because the air conditioner dehumidifies the air.

 

Yep I have had this happen it's normal, it went away after a few seconds so shouldn't really worry about it.

 

Are you operating the system in AUTO mode with A/C on?

 

Only way I know to stop is to turn up the temp. I usually tell my customers to set the temp to the same or higher than outside.

Otherwise don't put the air to the windshield.

 

I dont turn my a/c on only using the air from outside. the condensation is from outside.

 

Try leaving the A/C on. The A/C unit dehumidifies air as well. I leave mine on AUTO with the A/C on at all times and have no issues.