2018 Toyota RAV4 - foggy windshield

I have a2018 RAV4 with less than10000. miles on it. When we turn on the air and defroster , the outside of the windscheild fogs up the wipers will remove the fog but it just keeps coming back. is there a solution for this sort of problem? i hate driving around in the middle of summer with the heat at 78.

Turn off your defroster. It is causing moisture from the air to condense on the windshield. Yeah, I know it feels good blowing over the dash but moisture on the glass is the result.


You are getting condensation on the outside of your windshield because the a/c is cooling the windshield below the dew point. Direct your airflow to the dashboard vents.


Do you have auto temp ? And if so is this your first vehicle with that feature ? I also don’t understand the defrost position when running the air conditioner .

completely understand your issue! the other comments address what happens, but none addressed the issue of humidity and heat… need to have the air on the defrost when its raining or humid or snowing, so what i do is just clear the condensation off with the wipers… in other words there is no solution!

Try turning recirculate off, and only using defrost as needed,

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You can also try windshield cleaning clay. (They are sold under many brand names.) It’ll remove water drops, dirt, etc. It’s not a cure, but helps. (2 of my cars collected moisture bad enough the windshield went opaque in the wrong sun angles.)

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I clean my windshield with ammonia cleaner (windex etc) then rubbing alcohol, then apply 2 coats of Rain X, this does not eliminate outside condensation but makes it much easier to take off, fewer cycles of the wipers.

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Have you cleaned the inside of your windows recently? I’ve noticed the need for defrost drops considerably after I clean them. The dirt provides a place for water to condense - remove the dirt and the water has a tougher time condensing.

If you’re operating defrost, be sure that recirc mode is off. In my '16 RAV, recirc mode is automatically off when the defrost is on, so I suspect your '18 RAV operates the same way.

I guess the big question would be why it’s necessary to use the defroster in the middle of summer. Can you give us some more details as to why you’re doing that?

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The reason your window is fogging is probably because your AC isn’t working. When you run the defrost the AC cycles and acts as a condenser to remove excess moisture from the air thereby preventing the very problem you are describing. Get your AC fixed and your problem will magically disappear.

Except that the condensation is on the outside, not the inside. The air conditioner does not remove moisture from the air outside of the car.


The condensation is on the outside.

Yeah, I got that. I have found that if I keep the inside clean, the inside doesn’t fog as much, reducing the need for the defrost. If the defrost is off, hopefully the condensation on the outside will go away.

I noticed some drivers had this same problem in the morning, driving in Thailand. High ambient humidity, condenses on a cooler surface like the windshield. There may not be anything you can do about it other than keeping the glass cleaned and running the wipers as needed. But try running AC mode only to keep the passenger compartment cool, no defrost.

This is an old problem that I encountered when renting Toyotas over 20 years ago - but never had with other brands. There is indeed something in Toyota’s defroster-a/c setup. I’ve learned to be careful and keep one or the other off at certain times. Clack_jr is right - there isn’t any solution except to do as I do.

My former car had the same problem. I had to stop using Rain-X. Mist would still collect, but was less troublesome, so the sun blinded me less often. It must have been the glass they use because the 3rd windshield didn’t have the problem.