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noticed this just now. I started my car, I did not have the heated window button enabled on the console, yet immediately my mirrors and rear window started melting snow. I felt them and they were indeed warm.

is this normal? does the car somehow turn this on at a certain temp even if you don't have it turned on on the console?
 

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noticed this just now. I started my car, I did not have the heated window button enabled on the console, yet immediately my mirrors and rear window started melting snow. I felt them and they were indeed warm.

is this normal? does the car somehow turn this on at a certain temp even if you don't have it turned on on the console?
Yep totally. Its in the manual.
 

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Mine turn on whenever either of the heated seat controls are turned on and the engine is running.
 

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Yep totally. Its in the manual.
Where is it in the manual? I couldn't find it with a quick search.

Mine turn on whenever either of the heated seat controls are turned on and the engine is running.
I never noted that it only turns on with the heated seats. However I have noted that it will turn on itself.
 

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Where is it in the manual? I couldn't find it with a quick search.
It's actually in the Shop Manual, rather than the owners manual:


Rear Window Defrost

When the rear window defrost switch is activated, the BCM activates the rear window defrost relay (located in the BJB ). When the rear window defrost is activated from the switch, the rear window defrost grid is energized and the BCM supplies voltage to illuminate the rear window defrost switch status LED . The rear window defrost system may also be automatically activated as an extra load for accelerated engine warm-up, however the defrost switch status LED will remain off unless the defrost switch is activated.

The BCM deactivates the rear window defrost relay when one of these conditions is met:
• The rear window defrost switch is pressed when the feature is active.
• Ignition state is changed from ON to OFF.
• A predetermined timer completes.
• Battery voltage has dropped below a specified threshold (load management strategy).


I never noted that it only turns on with the heated seats. However I have noted that it will turn on itself.
What I meant to say was that, in addition to the heated window switch and the automatic activation for accelerated warm-up described above, turning on the heated seats in my SEL will also turn on the rear window defroster when neither of the above conditions apply.

Looking through the Owner's Manual, the Shop Manual, and the Wiring Diagrams, I can find no indication that it should do so, but it does. As does my wife's SE. I'd expect that it's a function of the Body Control Module software

It doesn't appear to be operating at the same power as when operated by the switch or during accelerated warm-up, as it takes several times as long to remove a similar level of frost, but the lines of the heater wires are apparent pretty quickly nonetheless.
 

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Where is it in the manual? I couldn't find it with a quick search.

I never noted that it only turns on with the heated seats. However I have noted that it will turn on itself.
Page 129 in the owner's manual:

HEATED WINDOWS AND MIRRORS (IF EQUIPPED)
Under certain cold weather conditions, the heated rear window and
heated mirror may turn on (without illuminating the light on the rear
defrost button) even though you did not push the rear defrost button.
This is normal operation. The system does this automatically to provide
heat to the vehicle interior quicker
 

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Page 129 in the owner's manual:
Page 129 of my 2012 owner's manual (Fifth Printing) is about changing the front side marker lamps and parking lamp bulbs. Page 119 of my version, which covers the heated rear window, doesn't mention what you posted at all.

There were at least five printings of the 2012 owner's manual, and they are apparently often quite different.
 

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Page 129 of my 2012 owner's manual (Fifth Printing) is about changing the front side marker lamps and parking lamp bulbs. Page 119 of my version, which covers the heated rear window, doesn't mention what you posted at all.

There were at least five printings of the 2012 owner's manual, and they are apparently often quite different.
Sorry the only manual I have is for my 2014. I guess they forgot some stuff in 2012.[8]
 
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