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Author Topic: Window frost on the Inside??? Back to Topics

Sophomore Author
British Columbia

Joined:Apr 2009
Message Posted: Dec 17, 2012 5:22:58 AM

So the front window of my car gets frost on the inside, I'm wondering why this happens? And what could be done to stop it?
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Champion Author Mississippi

Joined:May 2004
Message Posted: Dec 29, 2012 2:00:06 PM

With the high humidity found in the south, frost or fogging can be a recurring problem. I've found that cleaning the inside of the window thoroughly, then applying a coat of Rain-ex (or some such similar product) will keep these problems to an absolute minimum ....
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Champion Author Akron

Joined:Jun 2003
Message Posted: Dec 29, 2012 1:42:05 AM

You're leaking water somewhere inside
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Champion Author Vancouver

Joined:Aug 2011
Message Posted: Dec 28, 2012 10:18:57 AM

you either have moisture from the inside (wet carpet, heating system) or a leak somewhere that is causing moisture to get in.

[Edited by: hornet17 at 12/28/2012 10:20:02 AM EST]
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Champion Author Boston

Joined:Feb 2011
Message Posted: Dec 28, 2012 9:49:14 AM

Ventilation is likely the answer. I have had problems before with leaks that wetted the carpet.
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Champion Author Winnipeg

Joined:Apr 2011
Message Posted: Dec 28, 2012 7:58:58 AM

The majority of inside frosting problems that we see are from people running their heater systems without fresh air. Some folks don't understand how the fresh/recirculated air controls work and some are trying to avoid heating fresh air. Unfortunately, without at least some fresh air, your interior will turn into a humid sweat box and any humidity has no choice but to condense and possibly freeze on cool/cold surfaces. Wonderful way to obstruct vision and potentially lead to hold & rust conditions. Try adding a bit of fresh air by ensuring your 'fresh air' intake is open (or even cracking a window open for a short period) and your problem will 'evaporate'.
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Champion Author New Orleans

Joined:Aug 2011
Message Posted: Dec 28, 2012 7:43:14 AM

I had this problem once, and I think it was because the carpet got wet.
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Champion Author Ohio

Joined:Aug 2009
Message Posted: Dec 19, 2012 9:50:42 PM

If your car has a trunk area check what is in there that can hold moisture,some older cars developed a water leak at the rearwindow trim areas causing extra moisture in anything that will absorb it stored in the trunk,also door bottom vent weeps that let moisture out from between the inner/outer door construction may be plugged with debris inside bottom of doors. Then the front outside vent area may have debri and not letting trapped water out the exits at fenderwell areas.

When in defrost mode,blower on, raise hood,have someone watch for the A/C compressor clutch to be kicking in as you switch back and forth to reg heat mode.If not maybe check fuse panel for a relay fuse blown,loose,etc. associated with that area,Some floor mats hold excess moisture,check... GL
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Champion Author South Carolina

Joined:Dec 2010
Message Posted: Dec 19, 2012 8:23:16 PM

Hello Cityscape. Internal moisture is the root cause of the inside frosting of your windshield, but I want to focus on safety and possibly resolving the issue.

Here is the most important thing to remember, don't hit a frozen windshield with a full HOT blast of defroster air. It may crack the windshield. It is best to put the defroster heat on when the car is cold and allow it to warm up gradually. This is especially true with a windshield that may already have a crack or a rock ding. The high heat will cause a crack to "walk" across the entire windshield.

I owned a 1978 Toyota Corona LE with this condition, plus I had to climb through the tailgate to get in as the doors froze. I resolved the issue by carefully inspecting, repositioning some door gaskets and putting a generous coat of silicon on the rubber. I never had the issue again. You don't mention details about the vehicle, but age does affect rubber components and gaskets. Take care :-) . MGY
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Champion Author Montreal

Joined:Apr 2010
Message Posted: Dec 19, 2012 9:37:17 AM

This is due to entering your vehicle with snow and ice on your boots and then the carpet stays wet with the heater on. As the car cools the water is evaporating, which causes the moisture in the car to build up.There are a few remedies that i use during the winter months living in Montreal to avoid this condition:
1)If you have access to a shop vac, vacuum the water out of the floor carpets, or use one at a garage
2)On top of your mats place newspaper, but leave it in sections,the thicker the better, as this will absorb the excess water/snow/ice. It can be a little messy as the paper get wet but it does keep your carpet dryer.Replace paper as needed.

[Edited by: DasAuto92 at 12/19/2012 9:41:52 AM EST]
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Champion Author Chicago

Joined:Dec 2004
Message Posted: Dec 19, 2012 9:22:56 AM

It seems as though most suggestions apply to frosting of the windows after driving the vehicle. My one vehicle that had this problem had frost on the inside of the windshield before I even got in the car in the morning. I suspect that is what the original poster is refrring to.
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Champion Author Birmingham

Joined:May 2005
Message Posted: Dec 18, 2012 3:01:59 PM

You have moisture on the inside of the car, which tells me you don't have a well sealed window, or door first and foremost. Check all windows and doors to make sure they are closed totally first and then, if that doesn't work, check all weatherseals around windows and doors.

Good luck.
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Champion Author Winnipeg

Joined:Oct 2002
Message Posted: Dec 18, 2012 9:13:21 AM

I run full heat on the windshield, set the system for recirculating, and crack the front windows just a touch. It works well.
Now, if it is warm enough out that the windows mist before frosting on the inside, then I run the a/c onto the window for a couple of minutes.
I don't know why we don't have electric windshields. Didn't Ford offer them at one time, called Instaclear?

A couple of things cause frost on the inside. One is breathing, the moisture in our breath condenses on the window. The other is snow sucked into the vents if they aren't cleared properly after a fresh snowfall.

[Edited by: rumbleseat at 12/18/2012 9:16:13 AM EST]
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Champion Author Chicago

Joined:Dec 2004
Message Posted: Dec 17, 2012 9:38:15 AM

I had that problem with one vehicle.....first thing in the morning there was frost on the inside of the windshild. Never did figure out why.
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Champion Author Nashville

Joined:Oct 2005
Message Posted: Dec 17, 2012 9:33:58 AM

Use the defroster and if that doesn't work try taking it to a dealership service department. The should have a fix.
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Champion Author Boston

Joined:Jul 2005
Message Posted: Dec 17, 2012 9:33:02 AM

Turn on your AC w/the heat
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Champion Author South Dakota

Joined:Mar 2005
Message Posted: Dec 17, 2012 9:15:04 AM

You have moisture inside your car. That is why they frst up.
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Sophomore Author Virginia

Joined:Mar 2011
Message Posted: Dec 17, 2012 8:45:22 AM

If this is an excessive and persistent problem in a particular vehicle, you may have a slight leak in your heater core which introduces moisture to the cabin.
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Champion Author Lincoln

Joined:May 2009
Message Posted: Dec 17, 2012 8:32:16 AM

If you have a switch or lever on the climate control panel to switch between outside air or recirculated air, switch it to outside air in the winter to keep your windows from fogging or frosting and recirculated air for maximum cooling in the summer.

[Edited by: BT1288 at 12/17/2012 8:33:58 AM EST]
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Champion Author New Jersey

Joined:Oct 2005
Message Posted: Dec 17, 2012 7:59:32 AM

defrost mode should kick in the AC automatically...

if you're still having problems, your AC probably doesn't have freon in it & you may need to charge it up

the AC system de-humidifies the air
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Champion Author Massachusetts

Joined:Apr 2008
Message Posted: Dec 17, 2012 5:44:37 AM

Use your AC with heat. It will dry the inside.
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Champion Author Lexington

Joined:May 2005
Message Posted: Dec 17, 2012 5:29:35 AM

Turn your AC on and then turn your heat dial up to high and run both at the same time. I run my AC in winter and summer. This is how buses keep steam and frost from the inside of the windows.
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