Windshield icing up.....on the inside

[MikeyIs4Dcats]

I have a 2006 Mercury Milan. It has been very cold in Kansas the last week or so and lots of ice and some snow.

For several days now, my windows have been icing up on the inside. Is this anything to look into? Shouldn't the heater and defroster be drying out the interior enough that this shouldn't occur?

 

[Vetterin]

You don't have your recirculate air botton on do you? Or is this happening while the car is parked?

 

[Pacfanweb]

You may well have a water leak and your carpets are wet. Pull the carpets up in the front and reach under them to feel if they are damp. If so, you have a water leak. I see leaks on the front floorboards of these occasionally.

Otherwise, you need to run your defrost...recirc doesn't make much difference in this mode...the A/C runs on defrost, which helps with dehumidification. But most cars don't get ice on the inside of the windows unless there's water inside the car.

 

[manowar821]

Originally posted by: Pacfanweb
You may well have a water leak and your carpets are wet. Pull the carpets up in the front and reach under them to feel if they are damp. If so, you have a water leak. I see leaks on the front floorboards of these occasionally.

Otherwise, you need to run your defrost...recirc doesn't make much difference in this mode...the A/C runs on defrost, which helps with dehumidification. But most cars don't get ice on the inside of the windows unless there's water inside the car.

Well, don't forget that you track a lot of water in during the winter with the snow sticking to your shoes and then melting off in the car while you're driving.

 

[Vetterin]

Originally posted by: Pacfanweb
Otherwise, you need to run your defrost...recirc doesn't make much difference in this mode...the A/C runs on defrost, which helps with dehumidification.

Didn't think the AC ran at all under 40-45 degrees.

 

[Black88GTA]

Originally posted by: Vetterin

Originally posted by: Pacfanweb
Otherwise, you need to run your defrost...recirc doesn't make much difference in this mode...the A/C runs on defrost, which helps with dehumidification.

Didn't think the AC ran at all under 40-45 degrees.

If the AC is activated (but temp set on high) it'll blow hot air - but, it'll run it thru the A/C's receiver / drier, which takes moisture out of the air so your windows won't fog up (well, not as much anyway).

My Honda ices up on the inside all the time, but I have a known water leak.

 

[boomerang]

Originally posted by: Vetterin

Originally posted by: Pacfanweb
Otherwise, you need to run your defrost...recirc doesn't make much difference in this mode...the A/C runs on defrost, which helps with dehumidification.

Didn't think the AC ran at all under 40-45 degrees.

Once the underhood temperature rises enough, the AC will run. It's a temperature / pressure thing. Once the refrigerant gets warm enough, the pressure will rise enough to allow the compressor to run.

I agree on the water leak theory. Also the slush / snow theory. If you park in a garage, crack the windows open. My attached garage rarely gets below freezing. Some evaporation will occur with the windows down. It helps a lot.

 

[Pacfanweb]

Originally posted by: Black88GTA

Originally posted by: Vetterin

Originally posted by: Pacfanweb
Otherwise, you need to run your defrost...recirc doesn't make much difference in this mode...the A/C runs on defrost, which helps with dehumidification.

Didn't think the AC ran at all under 40-45 degrees.

If the AC is activated (but temp set on high) it'll blow hot air - but, it'll run it thru the A/C's receiver / drier, which takes moisture out of the air so your windows won't fog up (well, not as much anyway).

My Honda ices up on the inside all the time, but I have a known water leak.

Sort of correct, but the air actually blows through the evaporator, not the receiver/dryer.
And yes, it's to remove moisture from the air.