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2005 SLK 350
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233 Posts
Discussion Starter · #1 ·
Is the outside temp reading influenced by pavement and/or engine temp?
Does the outside temp reading influence cabin climate control?
*
Background:*
*
Coming home from work in rush hour traffic on a Chicago
"expressway" at 6pm, with the air temp per weather report approx
60 F, my outside temp reading on the dash was 83 F.* My heat
was set at 76 F in the cabin but was blowing cool air.* As I
exited the expressway onto residential streets, the reading
fell to 72 F.* Later in the evening, around 9 pm with the weather
report stating 53 F, my dash read 63 F. *

Thanks for any feedback.
 

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2008 SLK55 AMG
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837 Posts
The sensor for the outside temperature is near the left fog lamp assembly. It's a small black probe that sticks out, quite noticable by hand when washing the car. My guess is reflected heat from pavement in rush hour traffic may affect the temperature reading especially if you're at a standstill. I notice the temp. to be higher on just starting the car after being parked and drops when I start moving along at greater than 5 mph.

I believe the inside temperature is monitored by infrared sensors mounted on the console where the interior lights are. You'll see two areas (driver and passenger) with multiple small slits. I do not believe the outside temp. reading affects how the inside temp is regulated. Perhaps someone with more technical background in automotive engineering can shed some light in this matter.
 

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2005 SLK 350
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233 Posts
Discussion Starter · #3 ·
etyu said:
Perhaps someone with more technical background in automotive engineering can shed some light in this matter.

You sound pretty darn technically minded to me. . .thanks.
 

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2007 GL320 CDI, 2005 SLK350 and 2001 SLK320
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328 Posts
I find the outside temp reading is always significantly higher than the actual air temp in the warmer months. The error is smaller in the winter months. By way of comparison, my SLK320's outside temp reading is always within a degree or two of actual. Same for my wife's Lexus temp reading. As ETYU said, the location of the sensor seems to affect the reading.
 

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ML 350 (2008)
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24 Posts
I live in TX and my temp rose to 151 today and took quite some time to come back down. The pavement must have been. It was nearly 100 today.
 

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2005 SLK 350
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233 Posts
Discussion Starter · #6 ·
broadiea said:
I live in TX and my temp rose to 151 today and took quite some time to come back down. The pavement must have been. It was nearly 100 today.

Just goes to show everything is bigger/more in Texas.
I'm thinking Western Omelet on the hood.
 

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2008 SLK55 AMG
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837 Posts
I can smell the bacon, cheese, bell peppers, ham, bacon and sausage sizzling on the pan and cheese on top. Yum. Yum.
 
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