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Ice inside windshield

I have a 2010 TDI Jetta Sportwagon with a panoramic sunroof. I live in Minneapolis and periodically, when it’s very cold out (single digits above or less), I get a large amount of ice buildup on all the windows in the car. Sometimes it takes about 45 minutes of sitting with the defrost, a/c, and heat at fan level 4 at 82 degrees to clear it up enough so I can drive. If it’s really bad, that can happen, it can get cleared up, but if I get back in the car again, it will happen while I’m driving, too. The dealership has checked drip trays, recirculate valve, all a/c components, but cannot replicate the problem or fix it. Any thoughts?

If you and your passengers are not really careful about removing the snow from their shoes/boots before getting into the car, then you are introducing excess moisture into the car. In low temperatures, moisture=ice.

If you are sure that you are not using the HVAC system on the “recirculate” setting, if it is definite that the sunroof is not leaking, and if you can eliminate snow on footwear as a cause of this problem, then you should explore the possibility of a defective/leaking heater core. Yes, that is extremely improbable on a 2010 car, but that would be the only other possibility as I see it.

There’s moisture in the car, somewhere. Figuring out where it’s coming from is the trick.

I recently had this problem in one of my vehicles. I had a jug of water in the car that had frozen and cracked, and the water leaked out and I was getting frost on the inside of the windows. I removed everything that was wet and parked the vehicle in the sun with the windows open an inch or so and it’s mostly dried out now.

As VDCdriver mentioned, if the HVAC system is operating in the “recycle” mode it will trap moisture in the car. It sounds like you have more than just a little moisture, however. I’d be looking under the carpet for wet padding if I were in your situation.

I’ll have them check the padding - thanks! I’ve asked for them to get some rubber floor mats for me so that I can see how much water is accumulating from snow and they won’t because they’re convinced its not the problem, but I’m hoping I can try that soon, too.

Do you have the massive panoramic sunroof? Those seem to be more prone to leaks or having the drain tubes get clogged or disconnected.

I do that the sunroof you’re talking about. I think they checked the seals, but will run the drain tube thing past them again.

In this weather YOU’RE bringing in the moisture, Then locking it in.
Wet feet, snowy feet, icy shoes, snow scrapers all contribute.
The mats, even damp, don’t get a real chance to dry in the cold temps.

Wife’s 06 Escape hybrid. We use an unfolded cardboard box trapped under the wipers for frost abatement overnight.
A few days ago I went out to put it on and thought "oops too late, it already frosted over. "
–It was ALL on the inside. 100% of the windshield and most of the two front door windows.

Why ? As we drive off in the morning it’s quicker to just grab the cardboard from outside and drop it in the passenger floor until tomorrow not noticing that the frost that covers it soaks into the carboard as it melts. It sure seems dry tonight as we put it back on.
But, coupled with those floor mats that also seem dry, it’s just too much pent up moisture with nowhere really to go.

What did I do about it ?
Years ago when we had the first interior frost problems I put several pieces of blackboard chalk in variuos places inside the car. This helps tremandously for most of the normal wet snowy feet.
Last week I took the cardboard into the house to dry and turned the car’s heater on midway with one of the windows open an inch. Letting it run for an hour or so, an open window gives the trapped moisture somewhere to escape.

No problems since. Cardboard stored inside car each day since. ( southwest high altitude four corners weather )