We had new minivan (sienna), when it is raining/snowing lot of fog is coming, I couldn't able to see anything on the road, how to clear that?. (actually I turn on AC, put the heating/cool button in the middle), that is not helping at all.
Thankjs,
Dry the carpets is the first trick. Wet carpets cause lots of fogging.
Also make sure your heater isn't on recirculating air, have fresh air coming in.
Mike
86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT'sSanta wrote:
If the A/C is on, you should have it recirculate the air, then the air will continually lose water vapor as it goes through the evaporator core. If the A/C is not on, then you should not recirculate the air.
My recommendation is to set the temperature to the heat side and the fan to high with A/C and set to recirculate the air. If it's hot, you can leave it on the cold side but it's more effective with hot air.
-Bruce
|We had new minivan (sienna), when it is raining/snowing lot of fog is |coming, I couldn't able to see anything on the road, how to clear |that?. (actually I turn on AC, put the heating/cool button in the |middle), that is not helping at all. | |Thankjs,
Rex in Fort Worth
I have never seen that work in the winter up here in Canada.
Normally the carpets get wet and even with the AC trying to dry the air, there is no way the AC can make up for the water in the carpets using recirculating air.
I have seen it tried lots, it just doesn't work.
Recirc can get it warmer faster, but not drier.
My $0.02,
Mike
If it's relatively new, turning the controls to defrost (often vans have front AND rear defrosters) should clear the fog. If not, & is under warranty, get it to the dealership asap. If not, have the heater core checked for leaks--if it leaks a bit of anti-freeze, it will have to be replaced. Virtually nothing will clear antifreeze-laden fog from inside the windshield. HTH & good luck, sdlomi
Drive with the windows 1/7 open. I know, I know, rains get in.
Eat ice creams before getting in the van. Reject passengers with huge body mass (fat) or after they exercise. Look straight, don't move, breath thru your nose. I know, I know, there's no proof that these work.
Defrost setting. On most cars, this turns on the AC to dry the air. Also, make sure the vent system is set to bring in fresh air, not recirculate.
To reply, please remove one letter from each side of "@" Spammers are VERMIN. Please kill them all.
Wrong. If you want to clear the fog, the AC must be NOT be set on recirculate. The defogger only works correctly with fresh air coming in. The AC removes some moisture from the air, which aids in de-fogging. That is why most defoggers automatically turn on the compressor, but it does not remove it fast enough to make your scenario valid. The fastest de-fogging is by changing the interior air supplemented with the dehumidifying effects of the AC.
I think the answer to the original question is actually simpler - You need to set the AC controls to defrost. Simply turning on the AC does not blow any air at the windows. Look for a button on the AC control panel that looks like a picture of a window with a heating element in it. When you need to rapidly clear the windows, push that button. The car knows what to do. Check your owners manual if the controls are not obvious.
Wrong. The defogger works even without fresh air coming in. If it's humid outside, why would outside humid air be any better than the humid air inside. The original poster talks about when it's raining and snowy. Your blanket statement is inaccurate.
I was unclear with my post in the assumption that the driver was using the defrost setting and a independent A/C control. Obviously if you want to defog your windshield, it should be on the defrost setting. We are all in agreement that A/C will help defog the windows, it's whether it should be on recirculate or not. I still feel that recirculating the air through the evap core will be better than allowing fresh humid air into the car. Of course, I live in Texas where defrosting the windshield is not a common event.
-Bruce
I cannot think of too many instances where defogging is needed when it is not rainy or snowy. No, my blanket statement is not inaccurate. Your logic sounds great, but it is just plain wrong. Yes, the defogger blows air on the window when in recirculate mode and some benefit will be derived from that, but it works best with the A/C compressor on and the air flow set to fresh air. Ford and Nissan agree with me. Owners manuals to both brands state that recirculate should not be used when attempting to clear the windows. Introduction of fresh air is required for successful defogging. The recirculate button doesn't work (by design) on my Infiniti when the control is set to defrost.
I can relate to Texas (6 years in Houston, 18 years in Dallas). Things don't work the same way in Texas as they do in Chicago in the winter. But, if you want to hone your defogging skills, spend some time in Houston where the humidity is 100% every morning even when its not raining.
Low relative humidity air is required to dry and de-fog a windshield
The absolute humidity of cold air is darned low. Warm it up, and for every 10 degrees F it will hold a LOT (50 - 100%, i forget) more water. Simply by heating up 30 degree F (100% Rel Hum) air to 70 F the "relative humidity" will get down under 10%.
Described in the reverse, this is the trick AC uses to de-humidfy air. By cooling the air the water is made to "fall out", because cool air can hold so little water
So, outside air is usually (but not always) the best way do defrost or de-fog a windshield.
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