Frost Buildup on Inside of Back Window

[lamerking]

It seems that my back window fogs or frosts up during the cold nights. It only happens to the back window and no other.

Does anyone have a solution for this problem? There was mention in a locked thread to let the heat out????

[aris]

Open your window just a crack and it should clear up

[mazda lover]

Moisture in the car from your car mats? snow melts leaving water in the mats. But why only the rear window? I have a 2005 sedan and no frost in the car's interior windows, do you park your car outside over night?

[aris]

Moisture in the car from your car mats? snow melts leaving water in the mats. But why only the rear window? I have a 2005 sedan and no frost in the car's interior windows, do you park your car outside over night?

it shouldn't matter if he leaves his car out side or not....mine is always out side...i never park in my car in garge unless i am working on it..Sometimes mine does it to when its real cold out all i do is just open the in just a crack and it clears right up

[lamerking]

I leave my car parked outside at night. I do have carpet mats in the vehicle but I also have rubber mats on top. I'm the only one who sits in the car and therefore the water is on the driver side rubber mat.

But i'm still confused as to why only the rear window frosts up while others don't?

[mazda lover]

It seems that my back window fogs or frosts up during the cold nights. It only happens to the back window and no other.

Does anyone have a solution for this problem? There was mention in a locked thread to let the heat out????


No sure there is an answer, moisture is the cause for sure, back window leaking? any moisture-wet in the trunk? Sedan or Hatch? take the wet mats out when you park the car for the night and see if that makes a diff
try this and do a search there for more answers
http://www.mazda3forums.com/index.php?topic=97284.msg1922413#msg1922413

[tmpz]

I've just noticed this with my 3. I had frost all over the windshield on the inside and some below the steering wheel area. Maybe I didn't close the door shut...

[mazda lover]

I parked my car outside all day in the sun, at night when I got in the rear window had frost on the inside, sun built up some humidity in the car, if the car was in the garage, like I always do instead of in the sun I would not have any moisture build up inside the car...it just happens,

[3GFX]

It build on the bottom first right?

There are trunk vents near the rear window in the plastic cowl.

Essentially any moisture starts there from the trunk or the exterior, its because that area and the area of the front window are areas where outside air gets in first. The front comes from the front vents the rear from the rear.

It shouldn't be a huge concern, just defrost.

[Donutz]

Try running your ac for 10 minutes before you shut the car off. It should help to dehumidify the air. I have an 05 and the ac doesn't come on when I turn on the defrosters so I turn it on manually. I don't know if this changed in the more recent models.

[mazda lover]

Try running your ac for 10 minutes before you shut the car off. It should help to dehumidify the air. I have an 05 and the ac doesn't come on when I turn on the defrosters so I turn it on manually. I don't know if this changed in the more recent models.


yes your A/C does come on when it is in defrost, the A/C light does not come on indicating the A/C is on when the dial is in defrost, any position past 12 o'clock turns the A/C on...running the A/C for 10 minutes is way too long, waste of gas etc...unless you do it 10 minutes before you reach your destination..going to be kinda cold tho

[Hives]

just use the defroster, and your good =)

[Noisy Crow]

Is this appearing over night? Try parking the car the other way around and see if the build up switches to the windshield....

[Gizzmo_jr]

I leave my car parked outside at night. I do have carpet mats in the vehicle but I also have rubber mats on top. I'm the only one who sits in the car and therefore the water is on the driver side rubber mat.

But i'm still confused as to why only the rear window frosts up while others don't?

Shouldn't have rubber mats ontop of the carpet, safety hazard.

And like my car, the sun hits the front first in the morning so my back window is sometimes frosty, not usually thou.

[Zoom Zoom Boy]

Just use your rear defroster and if you want, you can also turn your vents to the window setting which will turn on the AC compressor which will draw moisture from the car when it heats...

[Ogata]

I have frost buildup inside my front windshield when I leave for work at midnight...any reason why? I blast my front defroster to max and after I drive about 10 minutes, the frost starts to melt.

[ds2chan]

I tend to have frost build up on my front windshield. It was so bad one time that I drove around my neighbourhood really slowly because I couldn't see anything. I had to wait for the defroster to melt the ice. then I had to wipe up the moisture with a paper towel otherwise it would just stay there and freeze up again.

[Bean]

I tried leaving the window open but it did not help. I think there might be a air leak somewhere in the car.

[1stMazda]

I get frost on the back window as well on really cold nights, sometimes on the windshield but its the back window for sure, i have the rubber mats but they do get lots of water, im sure if i cleaned my shoes a bit better as to prevent getting snow in the car it would reduce the problem considerably.

[gonzo25]

I tried leaving the window open but it did not help. I think there might be a air leak somewhere in the car.

An air leak? I would hope air can get in and out of your car or you may have a hard time breathing with the windows closed.

[Bean]

D'OH!!!! Homer moment

Sure took a while for someone to notice that too :)

[my3]

I have the same problem. Started with frost on the back window. Now I get it, too, on my windshield and sometimes on the front driver and pass windows. Dealer told me to take out the carpet mats, didn't work. Next was to keep the back seats down, didn't work either. Next, keep the mode on defog, got frost again the other night. They can't find any leaks. They said might need to replace cowl to fix the windshield frosting.

[Bean]

Dont expect the dealer to be willing to do that.

[liquidzyklon]

I noticed this issue too on my ride but it's not frost just condensation. I don't have wet carpets or mats since the car is new, I think it's just the cold air causing moisture to condense onto the windshields (the back first and then sometimes on the front). I just use the rear defroster and front defroster for a few min and it's gone.

My dad's civic does this too, but not as bad as the Mazda3.

[Crombie3]

This may sound ridiculous but this used to happen to me and it turned out that we had left a pack of Baby wipes in the back seat and on colder days it was enough to cause the glass to frost over, took them out and never happened again. (sadly I had it checked at the dealer twice before I realized my mistake lol)

[gonzo25]

Haha Crombie, that seems like a bit of a bonehead move. I am not sure you are worthy of the Mazda 3, why don't you go drive a Ford or something!?

[canes73]

I noticed this issue too on my ride but it's not frost just condensation. I don't have wet carpets or mats since the car is new, I think it's just the cold air causing moisture to condense onto the windshields (the back first and then sometimes on the front). I just use the rear defroster and front defroster for a few min and it's gone.

My dad's civic does this too, but not as bad as the Mazda3.

I had this looked at recently too (front windshield not rear) Dealer said that the cowl drain plug has a bend in it that was filling and freezing over on colder days. They cleared out the plug and sent me on my way. They said they would send notice to Mazda Canada about possibly changing the shape of the vent.

[macman_ca]

I thought I was loosing it, a new car frosting on the inside?? My usually does it on the back, but has a couple of times on the front. But the rear is the biggest hassle..... I've only had my car for a month now. No open liquids in the car...