A/C window fogging and defoster

[Coffinhunter]

First I must say that I hate the humidity in Florida.

Good, now that I have that out of the way. When I run the climate control on auto I have noticed, particularly early in the morning, that the vents that blow on the windshield cause the window to fog up. I am assuming that is because of the temp and humidity outside.

If/when I push the button that is for defrosting the window the temp is warm, regardless of the setting on the unit. Is there a way of controlling that temp? I searched the site and could not find anything.

[Meir]

Originally Posted by Coffinhunter

First I must say that I hate the humidity in Florida.

Good, now that I have that out of the way. When I run the climate control on auto I have noticed, particularly early in the morning, that the vents that blow on the windshield cause the window to fog up. I am assuming that is because of the temp and humidity outside.

If/when I push the button that is for defrosting the window the temp is warm, regardless of the setting on the unit. Is there a way of controlling that temp? I searched the site and could not find anything.

do you mean that when you set the AC to defrost (pressing the marked button)
you get hot air coming out the defroster vent?

[Coffinhunter]

Originally Posted by Meir

do you mean that when you set the AC to defrost (pressing the marked button)
you get hot air coming out the defroster vent?

yep. That is exactly what I mean

[Deserion]

Not sure if that can be controlled, though I know what you mean. My old Mercedes does the same thing.

[Meir]

If I'm not wrong, that is the way it's suppose to be.
If you want to get cold air thru the defroster vents, you have to press the upper right button (the one with the arrow up icon)
I will check it tomorrow in my car, and will let you know, if it dose the same.

[thstone]

The fastest way to get rid of condensed humidity on the inside of the windshield is to turn on the a/c, set the fan at max speed, and select the upper right button to direct all of the airflow to the windshield. The a/c dries the air and the dry air will evaporate the water that has condensed on the inside of the windshield in a few moments.

[Meir]

Originally Posted by thstone

The fastest way to get rid of condensed humidity on the inside of the windshield is to turn on the a/c, set the fan at max speed, and select the upper right button to direct all of the airflow to the windshield. The a/c dries the air and the dry air will evaporate the water that has condensed on the inside of the windshield in a few moments.

The humidity is condensed on the outer side of the windshield ( at least in my case ).
Here in Florida it's still hot and hummed. So when the cold air is cooling the windshield, the humidity outside the car is condensing on it.

Coffinhunter,
I checked it out today.
When I press the left button, I get cold air at full blast.
When I press the right one, the cold air will still come out of the defrosting vent, but the fan speed will stay
the same.

One question. When you turn the AC on high, to you get foam flakes coming out of the vents?

[Meir]

The question is do you get the flakes.
(the stupid iPad won't let me fix my spelling errors )

[Coffinhunter]

Originally Posted by Meir

The humidity is condensed on the outer side of the windshield ( at least in my case ).
Here in Florida it's still hot and hummed. So when the cold air is cooling the windshield, the humidity outside the car is condensing on it.

That is exactly the problem. I end up using my wipers to see..

Originally Posted by Meir

Coffinhunter,
I checked it out today.
When I press the left button, I get cold air at full blast.
When I press the right one, the cold air will still come out of the defrosting vent, but the fan speed will stay
the same.

Which left button, and which right button are you referring to?

Originally Posted by Meir

One question. When you turn the AC on high, to you get foam flakes coming out of the vents?

Nope, no flakes coming out of the vents. Just about everytime I get in the car the A/C goes to full since I have it on auto (gotta love Florida), and I have not seen that.

[Meir]

Originally Posted by Coffinhunter

That is exactly the problem. I end up using my wipers to see..


Which left button, and which right button are you referring to?


Nope, no flakes coming out of the vents. Just about everytime I get in the car the A/C goes to full since I have it on auto (gotta love Florida), and I have not seen that.

The "left" is the one I marked in the picture. The "right" is the one with the arrow up icon.
In my car both of them will blow cold air.
The reason I asked about the flakes, is because inside the AC air box there are flaps covered with foam. This foam is known to fall apart, and then the air flow inside the box, is not as it should be.
And yes, I use he wipers too
Sorry I couldn't help, but I can't figure out where the hot air is coming from.

[Meir]

By the way.
The way I avoid that, is not using the auto function and eliminating the defroster vent by pressing the center right button only.

[Coffinhunter]

Originally Posted by Meir

By the way.
The way I avoid that, is not using the auto function and eliminating the defroster vent by pressing the center right button only.

That is what I have been doing too. Thanks!

Curious that the defrost button (left) blows warm air and I can't adjust it......

[Cupocoffee]

I realize this is an old post, but I have found that when I have the air flow setting to come out only at the vents, I get condensation on the lower outside of the windshield as I live in high humidity environment. I notice that quite a lot of air still flows out at the windshield even though my setting is for the air to go only to the vents. My solution was to direct the air to come out of the vents AND the floor. There is very little air coming out at the windshield and thus my exterior condensation problem is gone.

[EZY]

Old post or not I'm glad to see the answer that may solve the same annoying problem I'm having..I also live in Florida n agree the humidity IS terrible..thx guys for the problem solving info..can't wait to try it!

[kiyakubuke]

searching and found this post. just recently noticed that the outside of my windshield is fogging up because the defrost vents are blowing cold air on the inside. around the same time this started I noticed pieces of foam coming from several of the vents. guessing there is a airflow flap somewhere that has a foam gasket that has dry rotted. I have always just left the AC setting to auto and this just started happening.

[particlewave]

While redirecting as much airflow as possible through the vents and footwell may work, it's only a band-aid.

As kiyakubuke said, the problem is that the flaps that divert airflow are missing foam and letting air through where it's not supposed to be.
The real solution is to pull every last flap and replace the foam with something that won't deteriorate. Not an easy job

[kiyakubuke]

Originally Posted by particlewave

While redirecting as much airflow as possible through the vents and footwell may work, it's only a band-aid.

As kiyakubuke said, the problem is that the flaps that divert airflow are missing foam and letting air through where it's not supposed to be.
The real solution is to pull every last flap and replace the foam with something that won't deteriorate. Not an easy job

just found this post. going to check this weekend.
Interior vent debris

[Meir]

this is a common problem in areas with high heat and humidity.
i have the exact same issue with my current (and 3rd) porsche.
the first one i fixed, because i had a leaking evaporator, so i had to get there anyway.
on the second i didn't care as it was my second car.
my current porsche is my daily driver, and this thing is really annoying me.
maybe a winter project all over again
AC question

[Alfieg23]

Same problem here. Solution is to either use your wipers periodically or redirect the air, fan on hi and the temp. to LO, from the defroster vents.

Regarding the foam flakes, I also have that issue. I have minimized it by (1) closing all the vents (2) turning the air on high (3) opening each vent individually with the shop vac nozzle up against the vent (4) closing that vent and repeating with each vent. It seems to blow the majority of the foam out and into your vac. You will need to repeat the process down the road if and when you start seeing foam behind one of the vents. I hope this helps.

[kiyakubuke]

so the problem with my vents was that the diverter flap next to the heater core had most of the foam missing. took it out, cleaned it and put new foam on it. everything is fine now.

https://flic.kr/s/aHskFqRr5e