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Discussion Starter #1
The exterior temp reading has been all over the map on my 2014 HB lately
The real temperature has been around the freezing mark (0c) and I have had it climb as high as 22c (70ish) and that was actually hauling down the highway at about 65mph
Not sure where the sensor is located to look for damage or something obstructing / insulating it to throw the reading off that much

I have watched it climb as well as fall [scratch]
Almost seems like it is reading interior rather than exterior
 

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They had to replace my sensor under warranty because of the same problem. I have a 2012 HB and the sensor is on the side mirror (passenger side I think)
 

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Discussion Starter #3
had the car in for an oil change this morning and they said the would look at it but likely would need a separate appointment

Of coarse they couldnt simulate
I got down the street a few blocks and away it went climbing
Drove back and showed them it actually happening
They think it is getting heat from somewhere else [slap]
 

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had the car in for an oil change this morning and they said the would look at it but likely would need a separate appointment

Of coarse they couldnt simulate
I got down the street a few blocks and away it went climbing
Drove back and showed them it actually happening
They think it is getting heat from somewhere else [slap]
Maybe touching the heated mirror?
 

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wasnt using the rear defrost , so mirrors were not on
From the 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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From the 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.
This sentence makes no sense [dunno]
 

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Assuming the manual is correct, it could help speed heat to the interior in two ways.

First, heating the rear window will remove a heat sink of the cold window.

Second, the extra load on the engine will help warm it up quicker to provide heat to the interior sooner than otherwise. This is the one I've seen mentioned before as the reasoning for this automatic action.
 

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Second, the extra load on the engine will help warm it up quicker to provide heat to the interior sooner than otherwise. This is the one I've seen mentioned before as the reasoning for this automatic action.

Alternator load would be less than 200 watts (worst case) for heated mirror and rear glass... this is less than 1/3 hp load on the engine.

Really doubt this... very minimal difference IMO.
 

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Wouldn't disagree with that either.
 

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Maybe they left out the word glass in the sentence, since the heat does not blow on the rear glass and is far away from any vents. Plus it would have a minor impact on interior temp of car.
 
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