[ButterRider 7]

These are some tips which might be useful to remove fog from windshield:-

1.Change your air source- Most cars come equipped with buttons that allow you to recirculate the air already in your car or to pull air in from outside. If your windshield is fogging, change the setting so the air gets pulled into the car from the outside. Look for the button that has a little car with an arrow pointing inside the car. Tap this so the light above it is on.

2.Lower the temperature in your car- Because fog is caused by differing air temperatures, getting the air temperature inside your car to match the air outside will reduce fog. Turn your car fans on the highest setting, and turn the air temperature down as cold as you can stand.

3.Turn on the defrost vent with cool air- The defrost vent will direct air straight at your windshield, but the cool air will help your windshield temperature match the air temperature outside. This can help get rid of the fog on your windshield.

[chandu]

Originally Posted by Abhineet Singh

Hey TBHPians,

I have been facing a peculiar problem when it comes to fogging. There is an AC vent which blasts air on the windshield, which leads to a small foggy patch on the windshield. Only the region receiving the AC air gets foggy, and I have not been able to find a setting to switch off the air blowing from the duct in the car (2014 Audi A4).

Any pointers for this.

The Primary reason for the windshield to fog up is the build up of moisture (Humidity) inside the car. Typically this only happens when the AC is set to recirculate mode.
A couple of things are responsible, normally when it is raining and the temperature is lower, the compressor will cut out and the air is just being recirculated inside the car. This builds up the humidity due to the breathing of the people inside the car.
In normal times when the temperature is higher and the AC compressor is running, it will condense the water and dry out the air. The first place that will fog up is the area exposed to the AC vent which will be colder than the rest of the area.

The other possible explanation is the outgassing of the plastics in the dashboard area, this typically happens over a period of time and will collect on the inside of the windshield and shows up clearly at night or during rainy times.

To avoid this happening, the best way is the keep the AC on when driving in the Rain and setting the AC to fresh air. I have noticed many people turn the AC off when its rainy and this leads to fogging up very quickly.
The other issue can be avoided by cleaning the inside of the windshield regularly.

Just my 2 cents, Hope this helps.
cheers

[Abhineet Singh]

Originally Posted by chandu

To avoid this happening, the best way is the keep the AC on when driving in the Rain and setting the AC to fresh air.

The other issue can be avoided by cleaning the inside of the windshield regularly.

Just my 2 cents, Hope this helps.
cheers

Thank you for the detailed explanation.

Yes, I did keep the AC operating for the whole time it was raining. The circulation is in "fresh air" mode by default. The issue is that the fog buildup at the center of the windshield affects the visibility, at least in my case. I wish there was an option to check the circulation. Still, the monsoons are coming again. Will experiment again. Hope your advice works.

Will try to clean the windshield more frequently, not that they are dirty.

[chandu]

Originally Posted by Abhineet Singh

Thank you for the detailed explanation.

Yes, I did keep the AC operating for the whole time it was raining. The circulation is in "fresh air" mode by default. The issue is that the fog buildup at the center of the windshield affects the visibility, at least in my case. I wish there was an option to check the circulation. Still, the monsoons are coming again. Will experiment again. Hope your advice works.

Will try to clean the windshield more frequently, not that they are dirty.

Good to know that I could help. Another tip is to use the defogger mode of your AC if the windshield fogging does not improve by using the other methods. This will blow warm air over your windshield.

cheers..