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Hi all

Now that the weather is on the turn I am starting to suffer with my windows misting up.

They start to mist before I get in the car (the cars around it are not misted) and then I have to sit and wait once I am in the car as the windscreen goes opaque with steam straight away.

The de mister clears it but this doesn’t seem right. I have looked for dampness in the carpets, boot, etc but seems fine.

Anyone else got this?
 

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Hi all

Now that the weather is on the turn I am starting to suffer with my windows misting up.

They start to mist before I get in the car (the cars around it are not misted) and then I have to sit and wait once I am in the car as the windscreen goes opaque with steam straight away.

The de mister clears it but this doesn’t seem right. I have looked for dampness in the carpets, boot, etc but seems fine.

Anyone else got this?

Its probably nothing, if you clean inside of your windows with certain products or wipe them alot, they cause windows to mist up more easily.

If you are really concerned, check if heater core has coolant leaking into it. If that happens the heater will blow water vapor, but it will also have a strong sweet coolant smell to it.

You can also buy a cheap digital humidity meter and check the humidity inside your car vs. another car that doesn't have mist.
 

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Its probably nothing, if you clean inside of your windows with certain products or wipe them alot, they cause windows to mist up more easily.

If you are really concerned, check if heater core has coolant leaking into it. If that happens the heater will blow water vapor, but it will also have a strong sweet coolant smell to it.

You can also buy a cheap digital humidity meter and check the humidity inside your car vs. another car that doesn't have mist.
Cheers, I too am thinking it’s probably nothing. I do wipe the windows (but not when they are misted!). No idea what the Jeep dealer may have wiped them with though.

Recommendation for what to clean them with to help prevent this (and not get streaks)?
 

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Cheers, I too am thinking it’s probably nothing. I do wipe the windows (but not when they are misted!). No idea what the Jeep dealer may have wiped them with though.

Recommendation for what to clean them with to help prevent this (and not get streaks)?
I generally just use windex.
 

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If you use the a/c then turn it off, it will probably mist the windows. The condensation lays inside and when you restart the moisture rises out of the ducts. This is one of my perennial complaints about vehicles with a/c -- if you run the defroster, the compressor runs unless it's below freezing outside. Basically, a defroster paired to the compressor is addictive -- once you start using it, if you shut it off, the windows will fog up, so you've got to keep using the defroster. Its a chicken/egg situation, and the chicken keeps on laying eggs!

This is not peculiar to Jeeps or FCA products. It happens with and & every vehicle that has the a/c linked to the defroster.

I'm told the reason the two are linked is so the compressor is made to work during the months you wouldn't normally run it. However, where I live we can go weeks, even months, without getting above freezing; even when we do, I don't necessarily need to run the defroster. A garaged vehicle doesn't need the defroster unless I'm out in freezing rain or snow, but if its that cold the compressor probably won't run.

The issue for me is getting into the car on a rainy 40F day and my coat is wet. That fogs up the windows and I have to run the defroster, and then I'm stuck running it the rest of the day for the above-mentioned reasons. The next morning, even if the rain stopped, as soon as air comes through those ducts, it will be moist air from the day before fogs up the windows.
 

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If you use the a/c then turn it off, it will probably mist the windows. The condensation lays inside and when you restart the moisture rises out of the ducts. This is one of my perennial complaints about vehicles with a/c -- if you run the defroster, the compressor runs unless it's below freezing outside. Basically, a defroster paired to the compressor is addictive -- once you start using it, if you shut it off, the windows will fog up, so you've got to keep using the defroster. Its a chicken/egg situation, and the chicken keeps on laying eggs!

This is not peculiar to Jeeps or FCA products. It happens with and & every vehicle that has the a/c linked to the defroster.

I'm told the reason the two are linked is so the compressor is made to work during the months you wouldn't normally run it. However, where I live we can go weeks, even months, without getting above freezing; even when we do, I don't necessarily need to run the defroster. A garaged vehicle doesn't need the defroster unless I'm out in freezing rain or snow, but if its that cold the compressor probably won't run.

The issue for me is getting into the car on a rainy 40F day and my coat is wet. That fogs up the windows and I have to run the defroster, and then I'm stuck running it the rest of the day for the above-mentioned reasons. The next morning, even if the rain stopped, as soon as air comes through those ducts, it will be moist air from the day before fogs up the windows.

To give more detail, the reason why the compressor needs to run is to drop the humidity. Without the compressor running, the car will just pump moist air from the outside (especially if it is raining snowing and RH is 95-100%). It would build up more and more moisture inside and would actually cause more window fogging. So the compressor needs to turn on and condense the moisture out of the air before its heated. You can only do this by cooling the air further down so the water condenses out. It doesnt run this way below freezing because if it were to be done below freezing, the condensed moisture would freeze and clog the drain. Plus, below freezing, air cant carry much water, so the need for condensation is minimum.
 

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To give more detail, the reason why the compressor needs to run is to drop the humidity. Without the compressor running, the car will just pump moist air from the outside (especially if it is raining snowing and RH is 95-100%). It would build up more and more moisture inside and would actually cause more window fogging. So the compressor needs to turn on and condense the moisture out of the air before its heated. You can only do this by cooling the air further down so the water condenses out. It doesnt run this way below freezing because if it were to be done below freezing, the condensed moisture would freeze and clog the drain. Plus, below freezing, air cant carry much water, so the need for condensation is minimum.
To a point. However, I've found the closest thing to a solution is to run the defroster hot so it warms up the windshield. Then when you turn it off and let normal outside air in, it won't condense on the warm glass.
 

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You have moisture build up in your car. Check for leaks, cowl, seals, floor pan. Put a box or two of baking soda. Arm and Hammer -- Fridge and Freezer works well for me. Run your air conditioner all year round. Additionally, clean your windshield and windows thoroughly on the inside with some good glass cleaner and a clean cotton towel. Solvents and dirt build up on glass attract moisture.
 
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