Auto defog is not a great system (G90).

Mike734

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Genesis Model Type
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Thread starter #1
I have noticed that when I leave my AC system in Auto it spends a lot of time with the front defog setting on (the little auto defog icon can be seen below the map). That means the air distribution is constantly being directed to the front windscreen when it should be sent to the floor for heating and the front vents for cooling.

I read the manual and it mentioned that the "Auto Defog" system might not work properly in temperatures less than 50 degrees F and that it can be disabled by pushing and holding the front defog button for three seconds. The yellow light will flash and the system will be disabled.

Fifty degrees? really? That seems ridiculous. I live in the Seattle area. It is less than 50 degrees seven months a year and even at night in the summer. That is not a great operating range. So now I run with the system disabled which works OK except that I have to push the defog button when it's cold and raining just like older cars. This situation is not acceptable for a car that aspires to be in the class of Mercedes, BMW and Lexus.

My Acura from 2006 handled air conditioning better. In auto, the AC system is always on thereby drying the air entering the cabin. Although this probably had a negative effect on gas mileage, the cabin air was dryer and fogging was generally not a problem. In severe conditions I put the defog switch on manually (just like I have to do now) and cleared the window. It appears that the engineers at Genesis have decided to forgo a better system in favor of better mileage. By the way, I can simulate the Acura system in the G90 by manually selecting AC "ON" when in auto mode. This does dry the air a little and delays having to manually select the defog button.

Does this match anyone else's experience?
 

EdP

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#2
I don't live in Seattle so I don't know your weather aside from a lot of rain. Has it always operated that way? Is it something that has changed since new? My only thought is that if it has changed perhaps something like a clogged cabin filter would affect it. I'm on the other coast and defrost does not go on very often here.
 

Mike734

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Genesis G90
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I don't live in Seattle so I don't know your weather aside from a lot of rain. Has it always operated that way? Is it something that has changed since new? My only thought is that if it has changed perhaps something like a clogged cabin filter would affect it. I'm on the other coast and defrost does not go on very often here.
I've only owned this car for one month so there shouldn't be any clogged filter problems. I imagine the problem stem from cooler air always being a little more humid than warmer air. I'm thinking the algorithm used to determine when to turn on the defog system is flawed, hence the warning that it doesn't work well below 50 degrees.
 

Riley2323

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#4
In the Northeast as well. I have yet to see fogged up windows. I use the defrost button periodically depending what is on the exterior of the windshield.

You seem to be jumping to the most complicated conclusion for a solution and bypassing some of the most obvious.

Not saying you are wrong, but it is just a matter of getting the right balance of temperatures or humidity to eliminate the problem. It is sort of a triangle of humidity, and interior temp being appreciably different than exterior temp, remove anyone of the legs of the triangle and the problem is solved.

Have you tried cleaning the interior windshield? I had my car serviced at the Hyundai dealership and it was spotless when returned, but the cloth they used on the interior windows had something on it and it left a god awful chalky residue. Thinking it was polish. That caused perceived foggy issues for me during a rainy stretch and until I mustered up the energy to clean them. The new materials can give off fumes too.

I think the dealership checking on filters is a good idea too.

Recirculation button working properly? It should be pulling in fresh air for defogging.

And what about just using auto climate? I rarely mess with anything other than the temperature and I know in the autumn it gets funky with humidity and strange temperatures in certain parts of the day.
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Mike Frantz

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#5
I live in the Seattle area and also have had issues with fog that I never did with BMWs and Audis.

Most noticeable with passengers when crossing the mountains (cold and rainy/snowy).

I keep it in Auto always but the fog gets thick enough especially in the bottom front corners of the door windows and base of the windshield.

Is it a regional thing? When I first moved here as a college student in 1989, my first cars lacked a/c. I realized I needed it not to stave off summer heat (usually below 80 degrees and low humidity) but to be able to see with the windows rolled up from October thru June.
 

EdP

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#6
I live in the Seattle area and also have had issues with fog
Is it a regional thing?
Seattle is wetter than most places. The average humidity in in the top category at 73. Atlanta is 68, Las Vegas is 30. Other factors come into play on a windshield though, temperature, temperature changes. air movement.
 

Riley2323

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#7
As they have engine warmers for Aslaska, MN, ND and Montana and a few other states, sounds like they need a NWest Package/program as Mike stated. They moved the Gas station data from the the Sirius controls to the home page on the dash, I am sure they could make a Rain Forest climate control setting toggle; if you hit the right person at the company.

Or maybe it is just as simple as switching out the interior sensor for a humid environment sensor.
 

Mike Frantz

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#8
Or I should just move :)

While I share Mike734’s experience in getting fog while on Auto, I’d say for me it’s only been a handful of times in 8500 miles. It obscured enough that I took action to clear it, and found it odd that Auto wouldn’t prevent it.

Each time it was below 40dF, raining of course, and I had 2 passengers on a long trip.
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Mike734

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Thread starter #9
I want to emphasize that I’m speaking of two different “Auto” systems. The auto button that make the entire AC system run automatically and the auto defog system. They are separate. The defog can be set to operate manually or automatically via the defog button. Hold it for three seconds to switch back and forth.

When mine is running automatically it offen turns on probably based on some sort of humidity sensor. The trouble with that is, very often that means the heating I expect from floor vents is directed to the windshield instead when not in fogging conditions. When I read the manual it said that the system may not work properly when ambient temperatures are below 50° F. We are often at or below 50° here in Seattle. Therefore I have set it to run manually. I have to turn it on.

In my Acura, when I push defog, the AC came on. I think most cars are the same. Turn defog on, the AC compressor come on. This does not seem to be the case in the G90. I have to also push the AC button. Seems wrong and a design oversight to me.

I’m hopping that later this spring and summer I can return to fully automatic but I’m doubting it based on the normal temperatures around here.
 

EdP

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#10
In my Acura, when I push defog, the AC came on. I think most cars are the same. Turn defog on, the AC compressor come on. This does not seem to be the case in the G90. I have to also push the AC button. Seems wrong and a design oversight to me.
You may have to pop the hood to see if the compressor is engaged, but having the AC run with defog is 40 year old technology. May be worth having the dealer check it out.
 

EdP

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#12
Are you suggesting that your compressor DOES come on when you push defog?
Not just suggesting, the manual says it does. Mine has worked well, but my climate is less severe with rain than yours.
This is from the G80 manual:

Auto defogging reduces the probability
of fogging up the inside of the
windshield by automatically sensing
the moisture on the inside of the
windshield.
The auto defogging system operates
when the heater or air conditioning is
on.

If more moisture is in the vehicle, the
automated steps operate as follows:
Step 1 : Operating the air conditioning
Step 2 : Outside air position
Step 3 : Blowing air toward the windshield
Step 4 : Increasing air flow toward
the windshield
______________________________
 

Mike734

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Genesis G90
Thread starter #13
I don’t see that in the manual. I’ll look again. It should. But then I disabled the auto function and that might have disabled that aspect of the system.
 

Akin67

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#15
I want to emphasize that I’m speaking of two different “Auto” systems. The auto button that make the entire AC system run automatically and the auto defog system. They are separate. The defog can be set to operate manually or automatically via the defog button. Hold it for three seconds to switch back and forth.

When mine is running automatically it offen turns on probably based on some sort of humidity sensor. The trouble with that is, very often that means the heating I expect from floor vents is directed to the windshield instead when not in fogging conditions. When I read the manual it said that the system may not work properly when ambient temperatures are below 50° F. We are often at or below 50° here in Seattle. Therefore I have set it to run manually. I have to turn it on.

In my Acura, when I push defog, the AC came on. I think most cars are the same. Turn defog on, the AC compressor come on. This does not seem to be the case in the G90. I have to also push the AC button. Seems wrong and a design oversight to me.

I’m hopping that later this spring and summer I can return to fully automatic but I’m doubting it based on the normal temperatures around here.
I picked up my G90 a week ago. Yesterday we went out in NJ where the weather was in the mid 40s and raining. I can understand the defogger kicking in when you have the HVAC in Auto mode. However, whenever you disengage the AUTO mode and select to have the air blow out of the floor, it should stay there. In my case although AUTO was off and I specifically and multiple times selected to have the air come out the floor vents so we don't have hot air blowing in our face, after one second it disengaged and automatically began blowing air out by the windshield again. No matter what I tried I could not change this. Finally I found this post and pressed on that button for 3 seconds to shut the defogger off. Once I did this, the windows did not fog up, leading me to believe the defogger was not even necessary in the first place. Why does the vehicle automatically switch to defog mode, when I manually set it, and also, why does it automatically switch to defog mode if it isn't even necessary? If it was necessary, wouldn't the windows have fogged once I turned it off?
 

EdP

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#16
Why does the vehicle automatically switch to defog mode, when I manually set it, and also, why does it automatically switch to defog mode if it isn't even necessary? If it was necessary, wouldn't the windows have fogged once I turned it off?
There is a setting in the setup to switch it off. Uncheck the box if it is checked. I don't know the threshold of what triggers it but mine rarely turns on and only when it is needed. One or two others did not like the auto setting either.
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EdP

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#18
Where in the setting would it be and what exactly is it called? It is not under the climate settings.

Thanks for your help.
G90 may be different but the G80 you use the steering wheel button (with the pages on it) on the right side. Page through and there is a setup page for many function.
 

Taxexempt

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#20
Where in the setting would it be and what exactly is it called? It is not under the climate settings.

Thanks for your help.
To cancel the auto defogging system
1. Press the Engine Start/Stop button
to the ON position.
2. Press the front defroster button
over 3 seconds.
3. The front defroster button indicator
will blink 3 times and then ADS
OFF will illuminate on the climate
control LCD display when the auto
defogging system is canceled.
 
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