I live in Wisconsin and do not have this problem with my 08. However, the first time I owned a toyota, this happened.

I quickly learned, like you, that running the AC in winter doesn't help much.

After some trial and error, I figured out that the fresh air/recirc button must be on fresh air when air temps get colder. The colder air can't hold as much water vapor so heating it as it is brought inside helps to dry out the interior.

If using the fresh air mode isn't working, then I suspect a problem with the fresh air damper not opening or the cabin exhaust vents being clogged (usually under the front seats of many cars). I'd insist that the dealer check this part of the ventilation system.

With that said, I have experienced this problem maybe once or twice in heavy rain near freezing outdoor temps. This is probably the worst condition for foggy windows. I assume that you are not experiencing this type of weather so often.




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schumy,

Strange for sure.

High humidity is removed from the car by the AC system (regardless of what temperature setting you have the climate control at). If you have fogging of the glass, either the AC compressor isn't turning on, there is a134a (used to be freon) leak and the AC isn't working even though the system says it is, you have a coolant leak into the cabin from the heater core (do you see sweet coolant?), or the car has a massive water leak that has the carpets absolutely full of water.

Keep in mind that even though there is cool/cold air coming out of the vents with the AC on, its winter and cool/cold air will come out of the vents if you have the temperature set low enough. What I mean, is if you feel cool air from the vents ... it doesn't mean that the AC made it cold. It may just be cool/cold outside air.

Another thing to consider .. is your recirculating air switch on or off? Try it in both modes while driving. It just may be that there is so much moisture in the outside air that in off mode (air comes into the car from outside) a weak AC system can't remove all of the moisture to unfog the windows. Then again, with the air circulation switch turned on, the AC should totally strip the moisture from the car, as it only has to cool/dehumidify the air in the car, as no outside air can be drawn into the cabin. I hope this makes sense, because now I'm confused ... i think. Good Luck and keep us posted.

Gene

 

Thanks for the replies guys. The air is always pulling in air from the outside, recirculating fogs up the whole car instantly. I've never experienced this with any of my previous cars, and any fogging was never this bad. Sometimes it's so bad that I get droplets condensing. I haven't see any coolant leaks. Maybe there's a a134a leak in the system, I wouldn't be able to tell myself.

I would like to be able to check the cabin air exhaust vents though i think they're behind the rear bumper. And I don't have access to the front vents to see if the fresh/recirculating is working. I park in an indoor garage while at work which is kept at 20C, I will attempt to turn on the AC and see if it has enough cooling power.

I'm going to make another appointment with the dealer and have them check everything out again on the ventilation system. If my dealer keeps saying there's no problem, I will go to a different dealership and have someone else take a look.

 

You never specifically mention if the condensation is on the inside or outside of the windows.

If outside, a minority of forum members have reported it for the '16 & '17 model years. I had the problem on my '16. When near the ocean and moist air the outside of the windows would flash-fog without warning and it was really hard to get rid of - the wipers were ineffective and the window would re-fog almost instantly as they passed over it. Time fixed the problem so we chalk it up to a coating on the glass from the factory. Perhaps a cleaning with some alcohol would accelerate the fix.

If inside and the A/C unit isn't helping but the dealer confirms it' function then you have a moisture problem. Is there a leak in a window seal somewhere letting a bunch of water in?

 

The condensation is always on the inside. I haven't seen any water leaking in from anywhere, but I will do my best to check all the seals and make sure water isn't coming in somehow.

The only other thing I can think of is that whoever cleaned the car before delivering it dropped a bunch of water in the interior, but I did a meticulous check before taking ownership of the car so I doubt it's that.

 

Haven't had this problem since I no longer transport that REDHEAD!

 

Very odd indeed. If the HVAC flaps are all working as expected, I'd really check under all the carpets for wet padding. Possible that the AC drain tube is draining inside the car instead of outside. Also the sun roof drains.

 

What is the outside temperature being registered on the display? I believe if it's below 45*F that the AC compressor won't kick on at all, regardless of the button being on.

I've been having this issue on my '05 and I can see that the AC compressor is not being turned on by the ECU until the car is warmed up. I couldn't see anything this morning.

 

This happens when the outside temp is below 33-34F, I was also thinking that it might be the AC not turning on... is there a way to find that out?

 

UPDATE:

So I got a humidity meter and put it on the windshield to check how A/C on vs A/C off behaves. And there is not much of a difference.

It was 40F outside, so I put the temp in the car to Lo with Max flow, and the humidity level would just rise with or without A/C.

When I would set the temp to something warmer like 66-67F, the humidity and put it on windshield then the humidity would drop.

I feel like there's a problem with the AC turning on/off

 

You'll never defogg or defrost with cool air, a/c on or not. Cool / cold air cannot hold moisture so it will not evaporate effectively. You have to turn up temps to warm air up and use fresh outside air. Warm air can hold a lot of moisture, thats why a clothes dryer heats up to extract moisture from clothes, even gas dryers that one of the combustion products is moisture are highly effective. A/C boosted defrost works because it removes more moisture before it is heated. Heat is the key.

A/c is ineffective at low temps and the compressor is usually locked out anyway. So set your temp dial to max heat, Recirc off and your windows should clear. As the windows clear dial down temps. This is one of those times you have to override the automatic system to get it to do what you want.

 

I should clarify, today I was troubleshooting the system to see how it behaved in different settings. The car will defrost if I blast warm air with the AC on, but the rear windows and windshield will still fog. The two shots in the first post are with the defrost blasting at max and the temp is set to 73. The issue is that I have to keep the windshield defrost on max to just keep the front windshield and two front windows from fogging up, the back windows never defog. It just seems like the AC system isn't capable of pushing enough dry air to remove all the humidity from the car.

 

It seems to me that the compressor runs when either of the defrost positions (full defrost button, or the windshield/feet setting) is selected, even if the A/C button is turned off. When the temps are nice in the spring and fall, I'll often turn the A/C off and just circulate outside air without chilling it; occasionally, the windshield will mist up and the defogger does a good job (and feels chilled and dried) even if without re-activating the A/C button. This is just my impression, though, without any actual measurements.

I haven't checked to see if this is still true when it's frigid out, but reports that the compressor doesn't run while in defog mode when it's cold outside were news to me.

 

I'll continue taking measurements to see what the humidity level is, especially in the morning since it's below freezing.

 

The strangest thing that has happened was driving normally on a highway and all of a sudden there might have been a slight drop in temperature, and the car (that was not fogged before) got instantly fogged up, all the windows at once.

This condition is certainy not normal but can be easily reproduced by switching to recirc mode. The dealer needs to fully evaluate this part of the system. I wonder if you could see the position of the fresh air intake damper if the cabin air filter is removed.

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Something else is going on then, an evap core full of water, fresh air door not operating, or a water leak in the car somewhere, and I'll tell you that that you may not realize it because the under pad may be soaked without the carpet feeling wet. My bet is the a/c drain hose is leaking into the cabin and or plugged, or the water from the bulkhead drainage area is infiltrating the car, or the fresh air door is not operating correctly.

Is the spare tire well dry? Seen those fill up too. Pull the door sills and feel under the carpet. They just snap in place. This is extremely unusual. A/c is not need to effectively defog or defrost, its just a booster.

 

I would be surprised if it were the A/C Drain leaking in... the car did this right off the dealer lot, initially I thought it was just humid because they had just washed it, but now after a month, it's definitely something else.

Going to take the car to the dealer again tomorrow and have them to a more in depth check. I don't want to start pulling stuff off the car right now as it's cold and I'm not sure how brittle those plastics get.

My troubleshooting is showing that in the morning the car is at about 50-55% humidity, which rises to about 70-75% before the heater starts blowing warm air in the cabin. I've checked that air, and it's definitely dry (below 15%).

 

Update following visit #2 at the dealer:

No problems found with the A/C, with the vents, no water ingress anywhere. They compared with another vehicle and apparently my cabin was 5% less humid... for what that's worth.

I will clean all the windows with invisible glass and stick in a dehumidifier in the car overnight to suck up all the moisture.

 

After reading this to the end, it seems that someone had missed some of that Subaru training they love to hype in the owner's manual!

 

You might have already solved this but I thought I would share my experience in case it applies to you.
I had the exact same problem as you described with my 2015 Outback with manual HVAC. Even with the defroster blowing full blast, the A/C on and the vent set to “outside air” the windshield was barely kept clear and only about 1/3 of the front side winders were clear. The back door windows and tailgate windows were completely fogged up. Not very safe and nearly impossible to park. I live in southern Ontario Canada. I bought the car about 4 months ago and the problem first occurred when the outside temperature dropped below freezing and the windows were cold. I took it to the dealer and he Declared that the system was “working as designed” and that the Fresh Air / Recirc vent door was working properly. They were wrong. I suspected that the Fresh Air / Recirc vent door was not working because I could not hear anything moving when I pushed the Fresh Air / Recirc button on the dash. The vent door is located behind the glove box just above the cabin filter. So I took out the glove box and trim and could see the door. It did not move when I pushed the control button. I noticed that the actuator located on the right side did not have a wire connected to the plug. There was a wire connection dangling there with right number of wires and colour of wires so I plugged it in and Voila...everything works. And the windows are no longer fogging up. I do not know if it came from the Subaru factory with this fault or whether this was a faulty repair on this used car, but it would be worth having your dealer check it out.
So before, I was simply recirculating himid air from the inside of the car onto the cold windows. But now the fresh cool & dry air enters the system and everything works. Sorry for the long post, but I just wanted to share my experience and hopefully it helps others.

 

Found the reason for the fogging! The electrical harness going to the fresh air flap was sheared off, therefore the flap wasn't opening to let air from the outside come in the cabin.

The dealer patched it back together, and it's behaving properly now!

 

Yikes! How did that happen?

Anyway... good to find the cause and thanks for the update!

 

I have been having this problem with my '16 Limited this winter but did not last winter. Will have to check the wiring!
Thanks!

 

Now that it's a few months down the road, is it still operating properly? I am having the exact same symptoms on my 17 Outback Limited and this is the second winter I have been dealing with them. Plan on taking it back to dealer again with suggestion they check out the wiring to the recirc/fresh air door. Thanks

 

Took 17 Outback back to dealer. Found unconnected wiring connector behind glove box. Connected and now seems to be working.

 

Hello!! So I have been having the same issue with my 2018 forester....I bought it last August and once the temperatures dropped in Nebraska I started noticing my windows fogging up and I was constantly switching my controls to get them defogged....and once they would get defogged they would instantly fog up again. Brought the issue up with the dealership and no one took it seriously. I was driving across Nebraska a couple months later when all my windows of course were fogged up and nothing would defogger them and even one of my backseat windows iced over on the inside!! I again brought the issue up with my dealership and showed them the photos of the iced window and again none of them believed me until I sent them an email. They finally looked at it and after a week said they found nothing wrong with my car....how did you find the electrical issue because I am frustrated with this issue for a new car and it’s extremly unsafe. Thanks!!

 

Non typical but.... I used Parts cleaner on a rag applied outside car and cleaned inside windshield it took off a film like residue and knock on wood.... it hasn't fogged up.

 

Welcome to the forum.:whoohoo:


The issue you are experiencing is caused by having moisture inside the vehicle and when the temperature falls you will get condensation. Think of a glass filled with ice water on a warm day. What is the best solution would be to rent/ borrow a portable dehumidifier and run it overnight in the closed vehicle. Otherwise running the heater for a few when you start the vehicle will help to stabilize the moisture issue.

Laughing at oneself and with others is good for the Soul![emoji2]

 

Hi CNicole
Yes, this is an annoying, and unsafe situation.
I posted a response to this issue early in this string. I have a 2015 Outback. I suspected there was something wrong with the inside/outside air Recirc door because there was no other source of moisture inside the car. After my dealer first declared there was nothing wrong, I decided to check the door myself. I could not hear any “action” behind the dash when I pressed the “Recirc” button, so I suspected it was not working. Using a shop manual, I was able to remove the glove box and some associated trim and the cabin filter and could see that the door was not working. The wiring harness to the door was not connected (it was just hanging there). So I connected it, and the problem was solved. Based on other responses earlier in this string, I suspect this might be a Subaru factory quality issue. So I suggest asking your Subaru Service dept to specifically check if the wiring harness to the door actuator is either disconnected or faulty. It was a really easy repair for an amateur like me, so a Subaru service tech could do this in about 30 minutes.
Good luck.

 

Hi CNicole
Yes, this is an annoying, and unsafe situation.
I posted a response to this issue early in this string. I have a 2015 Outback. I suspected there was something wrong with the inside/outside air Recirc door because there was no other source of moisture inside the car. After my dealer first declared there was nothing wrong, I decided to check the door myself. I could not hear any “action” behind the dash when I pressed the “Recirc” button, so I suspected it was not working. Using a shop manual, I was able to remove the glove box and some associated trim and the cabin filter and could see that the door was not working. The wiring harness to the door was not connected (it was just hanging there). So I connected it, and the problem was solved. Based on other responses earlier in this string, I suspect this might be a Subaru factory quality issue. So I suggest asking your Subaru Service dept to specifically check if the wiring harness to the door actuator is either disconnected or faulty. It was a really easy repair for an amateur like me, so a Subaru service tech could do this in about 30 minutes.
Good luck.

GOOD CATCH!


Bill

 

For anyone still having this problem, the humidity has to contact the glass directly to cause fogging. Clean the inside of the window, then spray pledge furniture wax on it and wipe until clear. The wax residue eliminates fogging.

 

Hey guys, first a big hello to everyone on here as this is my first post. Super happy to be a new member of the Subaru family!

I just picked up a brand brand new 2018 2.5 limited, and since the first day I got it I've been having problems with the windows fogging up. I live in Canada and now with the low temperatures this is happening VERY often and with extreme effects.

I've tried everything, AC on, Fresh air recirculating, opened windows, defogger. Nothing seems to work 100%. The front windshield and the driver and front passenger windows will get defogged after a while, however the back and rear passenger windows never end up getting defogged.

I always run the AC because of this and the climate control is on windshield and feet most of the time. The strangest thing that has happened was driving normally on a highway and all of a sudden there might have been a slight drop in temperature, and the car (that was not fogged before) got instantly fogged up, all the windows at once.

I've been to the dealer and they're saying there's no problem, the AC system works well, and no problems with the climate system.

Do you guys have any suggestions on how to start troubleshooting this? I'm really out of ideas aside cleaning all the windows on the inside with some invisible glass.

Here are some photos:

Same issues it's been 2 years and I'm so disappointed. To the point I may trade my crosstrek in. I've NEVER had this bad of an issue.

 

As covered in more than one of these threads, you likely either have a wet spot in the vehicle (check footwells and spare tire), or you have a malfunctioning HVAC that's not letting fresh air in. Occasionally this problem is also traced to a combination of climate and bad habits with HVAC settings. IMO, you should use recirc mode sparingly, as this almost always makes things worse. I'd also avoid using the A/C to combat an unknown condensation issue. As already suggested, the first step is to ensure the car has been thoroughly dried out, then you can begin to diagnose.

 

So tonight my Son inlaw and I applied parts cleaner to a rag and cleaned windshield...I drove 2.5 hours home and NO inside FOGGED WINDSHIELD..... It even took away the suction cup marks from intial instalation.