Very Serious Window Fogging Problem (HELP!)

Here's the situation, it's cold here in Ohio now, so I can't turn on the AC, or roll down the windows. I don't smoke, I have tried numerous glass cleaners, and I have used Rain-X Antifog. The defrost works but as soon as I turn it off the windows fog in less than a minute. I checked for water leeks and found nothing. I have tried with, and w/o the air recirculate, still doesn't work, and I refuse to rub a bar of soap on my windows.

Can anyone tell me how the hell I can stop this fog?

Use the defroster with the A/C on.

It is pretty much your only option.

~v6

Hold Your Breath as long as you are in the car :lol:

Hold Your Breath as long as you are in the car :lol:This answer is a perfect example of the kind of ******* I have been seeing since I joined the Forums. I get on here looking for good advice from someone who may have had the same problem, and I get a half a$$ answer from someone like DumbUglyDragon, who's nothing but a post whore....

The moderators on this forum really need to start regulating a little more because ******* like this makes good people, with good reply's and good questions want to steer clear.

I think that by running the A/C even with the heat on, you'll at least be removing water vapour from the car.

Yea, it doesn't matter if its cold - you should always run the defroster with the AC on. I don't know what kind of car you have, but if its an '02 or above the AC is automatically switched on when you turn on the defroster...

Car is an 02, only thing wrong with running A/C all the time is your always running the condensor. So in return, your burning more gas, and wasting power. Their has got to be a reason that the windows fog as bad and as fast as they do. If I can find out why this happens, I can find a way to fix it.

I've had that happen in 2 different vehicles over the years (85 Ranger, and GMC3500) both times the cause was a pin hole in the heater core.

Use the defroster with the A/C on.
I'm pretty sure it engages automatically anyway.

Any reply is a free bump. You'll never get away from such things on a public forum. No need to flip out.

THe cure is don't run the air on recirc. Use air coming from the outside. You know the little car with arrows switch. Also don't forget to select the air to be going to the windows only. No AC necessery.
I guarantee you it will work

ive noticed the same problem

i usually run the heat on the window def only with the air coming from the outside

-Jeff

THe first step is to clean your windows...dirt causes moisture to gravitate towards it.

I use a watered down ammonia/water when it gets bad, and I use newspaper for touchups.

In my experience (and I have lived in cold weather and now live in warmer weather, but we still get fogged windows), the windshield will continue to fog until it reaches approximately the same temperature as the inside air. Take your bathroom for example. The mirror fogs up until you open the door...then once the bathroom reaches the same temp, the mirror starts to de-fog. If you close the door before it is finished, it will take longer. Same concept (kind of).

Seeing that it is colder now where you live, instead of using the heat full blast, put the fan speed on medium or so and lower the temp a little. Should help. You might have to keep it on a little while longer, but at least you wont sweat to death with the heat on.

Well, my car used to do that continually. it was bad. really bad. Used rain-x anti fog and that helped a LOT. But didn't solve the problem. Then I opened the trunk one day to get something out and noticed condensation on the lid. Then I took out the spare to reveal more water. Apparently there's a hose of some sort (on my car, dont think it's on the newer cars because I think it's for drainage from the sunroof) that goes into the trunk. The hose had gotten dislodged from the bulkhead that it was supposed to go into, and so i had a nice big puddle of water in the back of my car.

Not too much info for you there, but I suggest waiting till the middle of winter (when the air is VERY dry), opening all your windows/trunk/etc, and just let the car air out. This will get rid of some/most of the H2O and decrease the fogging.

that's the best I can do you for, I could be wrong and the WRX has the same hose, but i doubt it. If it did it'd be on both sides of the trunk, but you have to take off the carpeted parts on the side to see it. Right next to the pressure vents (little rubber flaps that equalize the pressure inside the car with pressure outside the car).

I might take pics tomarrow, i've got 3 or 4 things to take pics of, lol.

I signed up just for this thread. I hope my post will provide some guidance.

For moisture, you could try to get some desicant (spelling may be off). Its the same stuff you find packaged with computer products, clothes, shoes, ETC. Its a silicon based product and it sucks moisture out of the air. I once spilled a gallon of antifreeze behind the passenger seat of my GSX, BIG BOO BOO. well, I got a hold of a very larg satchel of this stuff and put right on top of the wet carpet. 2 days later the wet spot was gone. I think it worked. I actually got two more bags and it seemed to keep moisture down to a minimum. I never had a window fog up issue. Desicant sucks the moisture right out of the air. To "recharge it" yuo throw it in the microwave for a few minutes. Doing so will allow it to suck up more moisture.

Maybe this will help. Maybe not, but at least its is better than that jerk off's post about not breathing anymore. :cool:

As was stated make certain you're not recirculating air. Pushing around warm and moist air is not going to be much of a help.

And yes running the A/C is a good idea when you need extra defogging capacity (even with the dial turned to "hot") specifically because it helps to remove humidity from the air. Granted this will consume more fuel because it's running the AC compressor; however if the humidity is so bad that your windows are fogging it's better to burn a little extra fuel for a few minutes to get the humidity out than it is to get in an accident because you cant see.

Running the AC with defrost a good idea. It's such a good idea that Subaru already thought of it. They do it automatically, just ask this guy: (from a different thread)
The AC compressor will run automatically when in defrost mode without pushing the AC button and the AC light won't be on. If you want to have fully independent control of the HVAC and compressor operation there is a mod to disable the microswitch that engages the compressor in defrost.
Check your A/C operation if you notice more fogging than usual. I find that this car is just bad for fogging up. If I'm driving with 3 passengers, I almost always have to crack the rear windows.

I'm pretty sure it engages automatically anyway.

You are correct, and that is a big part of the problem this guy describes. Once you turn on the defrost, you must keep it on or the windows fog almost immediately due to the condensation that occurs in the HVAC system making the cabin air very moist. It is true that the defrost works better with the A/C on, but it would be nice to have the option of using the defrost without it. I've had lots of cars without A/C and the defrost worked just fine with the lever set to fresh air. But without doing some re-wiring, you just have to accept that once you turn on the defrost, it stays on.

it would be nice to have the option of using the defrost without it.
-- Search the other forums for the details on the micro switch disable.
It should be at the selector knob for the vents (floor, face defrost, etc.) just under the fascia.

I had a SERIOUS fogging problem on my car. It was so bad that on a cold morning every single window in the car would be completely white before I even got in and would stay that way for a long time. Like yourself, I tried rainX only to find that it results in terrible window glare. I tracked the problem down to soaked interior matts and carpeting; that is where the moisture was comming from. I took the matts out and put them in the dryer and I ran the car with the heater on max, floor vents open and windows partially down for half an hour; the problem went away completely.

my 05 STI fogs a lot also.. and I always let the air outside to come in.. doesn't help..

Perhaps some of this will help.
On the Impreza both defrost positions run the a/c compressor. Like it or not you are stuck with that fact (unless you want to disable the switch).Personally I would like to choose when to run the compressor but it just aint so. It will always be very difficult to keep the fog off the windshield in a cold and humid climate without selecting one of the 2 defog positions.I am also of the opinion that the air movement in the car is not the best i've seen and therefore often have to drive with a window open a small amount or the windows will not clear well.Again that is just a fact with these cars.
That being said there are a few things you can do to help.
As was said prev.make sure you have no heater core leaks. In a 2002 car that really should not be an issue.
If you are not already then become very fussy about bringing any snow into the car and also about keeping the floor mats dry.
Make sure that the fresh air intake is never plugged.
Make sure that the fresh/recirc lever is functioning correctly.If it were stuck in recirc nothing else you do will help.
Use rubber floor mats for the winter, it's nearly impossible to keep the carpet mats dry in winter.
Don't know if your car lives inside or out but if you can dry it out completely once a month or so that will help a lot.
Sorry about being a bit long winded.

If it's a bad problem in your car I'd suggest running the A/C for extended periods of time while driving (even with the climate control set to "hot") because it will help remove a lot of humidity

If it's a bad problem in your car I'd suggest running the A/C for extended periods of time while driving (even with the climate control set to "hot") because it will help remove a lot of humidity
and vents set to outside air, crack a window (trying to get old, wet air out, and new dry air in).

Pretty much what everyone else has posted... lol

I've had this happen a couple times myself. I turned my vent selector to floor/windshield with the heat on high. I let it run till the fog went away. Then i turned the switch to floor(to stop running the ac) and i found the hot air still comes out of the windshield vents. This seems to keep the fog from re-forming without having to keep the ac on. Good luck.

-- Search the other forums for the details on the micro switch disable.
It should be at the selector knob for the vents (floor, face defrost, etc.) just under the fascia.


It's a very easy mod. Remove fascia & pull gain access to the HVAC controls; as you rotate the dash dial to the Defrost selections, you can see the microswitch being actuated. It's mounted with one small phillips (IIRC) screw...just unscrew it, and tuck the switch out of the way. You can restore the functionality by remounting the switch, if desired; AC operation in defrost mode can always be selectively added by pushing the dash AC button, anyway.

Again, for defrosting/removing moisture, ALWAYS have vent selector set for fresh air intake, never to "recirculation".

You might check your cabin air filter, too.

If the windows don't fog up when your not in the car then it has to do with you. I have the problem of rapid fogging only when I drive into underground parking on cold days. Otherwise just use the AC defrost.

Why does it fog up, because it is more moist inside your car then outside. Except when you go into an underground parking garage. Then it is reversed.

Don't use those anti fog things in your car, they smell terrible.

And don't use any air fresheners in your car either.

I used to play Ice hockey, and had a clear shield. I would use special anit fog stuff, and it would never fog. Could always try that. It lasted a long time on my clear mask, so might be worth a shot. Just go to the nearest sporting goods store, I think Dick's should have it. I might try this too, I hate it when my window fogs. Seems like it takes forever to clear.

Anyone know if the AC comes on automatically while using Bi-Level?

It occured to me that my rarely ever having issues with fogging may be somewhat related to my frequent use of bi-level and the reduction in moisture this is bound to cause.

Of course I'm sure it helps at least somewhat that I garage my car as well.

Anyone know if the AC comes on automatically while using Bi-Level?

It comes on in (Defrost) and (Defrost & Floor) modes.

If you have a HEPA filter check that out. It’s hiding behind the glove box. I got odors and fogged windows. I would have thought it was a heater core leak but it would clear after 10 minutes or so and I never saw a heater core leak do that. My car had 70K, I just plumb forgot it had a cabin HEPA filter. The half-inch of crud was holding moisture and odors. I cleaned it out in a bucket of hot soapy water. Odor and foggy windows are gone! Do a search there is a good thread regarding changing the cabin HEPA filter.

My L used to fog up pretty badly. I just dealt with it in the winter time. I couldn't ever find a good setting for the defrost.

Mine is fog-free now. Left the doors open for about an hour after it had snowed, now all I have to do is use the defrost when I see fog (although it is rare).

Bi-Level if it is like the GM HVAC systems is a setup that runs AC through the dash and floor vents, its one of the many AC modes. but this only applies to systems that do not have a seperate AC button.

THe cure is don't run the air on recirc. Use air coming from the outside. You know the little car with arrows switch. Also don't forget to select the air to be going to the windows only. No AC necessery.
I guarantee you it will work

I live in Northeast PA. I had the same problem. It was so bad I backed into a pole cuz I couldn't see. You absolutely want to turn off the recirc. or crack the window. you need that fresh air circulation. :)

I live in Northeast PA. I had the same problem. It was so bad I backed into a pole cuz I couldn't see. You absolutely want to turn off the recirc. or crack the window. you need that fresh air circulation. :)
Yeah, on warmer winter days, i'll turn it onto the foot position, and pop open the moonroof.

Although this has fixed the fogging problem, I have another problem.

If I let the car sit in the cold, but in the sunlight, i'll get frost on the inside of the window???? Now THAT sucks.

Hot air on full blast using the outside air.... the ultimate combination

I have a RSX and it fogs really bad, my WRX never has this problem. However the front driver window does not seal well after I had the window tint installed. I have to roll it down and back up to make it seal. Maybe that is happening on your car.

EDIT: Just realized this thread is uber old.

I use defrost mode with hot fresh air and pop the moonroof a bit (with the sliding inside cover closed).

Couple things I'm going to check after reading this thread:

1) Make sure the trunk is dry - everytime I open the trunk, snow falls inside. I notice the bottom of the rear window likes to fog, right near the vents from the trunk.

2) Dry out floor mats.

3) Adjust the AC drainage tube near the downpipe. The tube is bent into a new position because of the divorced downpipe and I think it is restricting water flow (picture a garden hose folded over itself). My mechanic said that might cut down on humidity removal and is usually the cause of "stinky vents".

DAMN THE FROST ON THE INSIDE WINDOWS!

something else to note even though this thread is old, it comes up every year.

those who have RS's pre 2002 subarus the A/C does not automatically come on with the defroster, you have to turn it on yourself.

I agree that subaru's are the worst cars I have ever owned with the fogging issue.