# Temp reading on dash



## MaximusPrime (Mar 23, 2011)

Mine is always quite high. 5-10 degrees hotter than it is outside.


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## audog (Apr 28, 2011)

about 4-5 degrees above.


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## Big Tom (Mar 8, 2011)

About 4-5 above for me too, unless _*ALL*_ the banks around here are wrong


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## rgblack316 (Apr 4, 2011)

you have to consider the temp. sensor is low on the car. it is in the bezel in the fog light opening. the road temp is usually a bit higher than the air temp since asphalt and concrete both have much different heat dispersant properties than the air does. They will be warmer and will reflect off more heat making the sensor show a higher temp.


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## gizmotoo (May 27, 2011)

In very hot weather (above 90 deg), mine also reads about 3 to 5 deg above that temp stated on the local radio station.


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## audog (Apr 28, 2011)

rgblack316 said:


> you have to consider the temp. sensor is low on the car. it is in the bezel in the fog light opening. the road temp is usually a bit higher than the air temp since asphalt and concrete both have much different heat dispersant properties than the air does. They will be warmer and will reflect off more heat making the sensor show a higher temp.


If the sensor is in the bezel for the fog lights, it only makes sense that it is reading a temp that is closer to the pavement temp than the actual air temp. It would seem that design engineers would also know that pavement gets warmer than the ambient air temp, so why don't the designers calibrate the readings to take this into account? Or maybe move the sensor to a more accurate position?


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## rgblack316 (Apr 4, 2011)

Take a look at the bezel on the front driver's side and you'll see a little silver sensor in an inset opening, that is the temp. sensor on the Cruze.


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## scaredpoet (Nov 29, 2010)

If you borrow or get an Infrared temperature gun and point it at the sensor, you might get an idea for how accurate it really is. Though you have to be careful that the temp gun isn't reading other things, like the temperature of the engine which is also giving off heat when running.

Just keep in mind that every thermometer isn't _really_ telling you the temperature of the environment, but the temperature of the actual thermometer itself, and those temps are always going to be different. The temperature that a radio station tells you is based on some weather station that could be miles away from where you are. 

And there's no telling where a bank sign is getting its temp from: it could be from the same source as that radio station, or it could be a temperature sensor attached to the sign itself or some other location. 

In any case, they're all intended to give just a general idea of how hot or cold it is. But it's never going be exactly the same across a whole city. We've just grown used to assuming that because it's more decisive for a weather person on TV to say "it was 101 degrees F today" than to say "yeah, it was really hot!"

One thing's for sure: none of those other sensors are on your car, facing the same conditions as the temp sensor feeding your dashboard display. So they can't be used to see whether your car's thermometer is precisely accurate. It's all going to be relative and general.


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## audog (Apr 28, 2011)

One thing's for sure: none of those other sensors are on your car, facing the same conditions as the temp sensor feeding your dashboard display. So they can't be used to see whether your car's thermometer is precisely accurate. It's all going to be relative and general.[/QUOTE]

I can live with it being "relative and general", I just find it odd that it is consistently 3-5 degrees above any of the drive by temperature displays, plus 3-5 degrees above my own outdoor thermometer when parked right next to it. But, having grown up when "it sure is hot" would have been a viable weather report, I can adapt.


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## 70AARCUDA (Nov 14, 2010)

...FWIW, the "temp" values on our 2004 and 2009 Pontiac Vibes (nee' Toyota Matrix) are typically within 1-2ºF of the actual air temperature (measured with home weather station sensor).

...there's no excuse for the Cruze "temp" values being 4-5ºF high...it's just poor GM "over-engineered" programming.


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## cruze01 (Mar 25, 2011)

Have you guys also noticed that it is very slow to change? Sometimes mine reads the same temp all day all over central KY, I hardly believe that could be accurate.


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## boats4life (May 28, 2011)

I think I must have bumped it or hit it or something when I was changing the CAI over- it read -40˚ today when I got in!!! Cool feature though, the DIC said that ice was a possibility and I should drive carefully. Thanks, Chevy! =] lol


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## LJG (Jun 8, 2011)

audog said:


> so why don't the designers calibrate the readings to take this into account?


Because the temperature reading is supposed to warn you of ice on the road, so you need to know the road surface temp rather than ambient air. If the road surface is warm from either residual sun heat or from traffic friction there is less chance of ice.


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## 70AARCUDA (Nov 14, 2010)

LJG said:


> Because the temperature reading is supposed to warn you of ice on the road, so you need to know the road surface temp rather than ambient air. If the road surface is warm from either residual sun heat or from traffic friction there is less chance of ice.


...ah, sorry, but the GM engineers aren't gonna get much "road" information from a sensor that's pointed straight ahead, down the road way!


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## stevenm (Jun 21, 2011)

I didn't buy my car for the temp if it's close and gives me an idea I'm happy. there are two many good things about the car to be wasting time about the temp. every car I ever owned has has been poor with this move on


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## gman19 (Apr 5, 2011)

stevenm said:


> I didn't buy my car for the temp if it's close and gives me an idea I'm happy. there are two many good things about the car to be wasting time about the temp. every car I ever owned has has been poor with this move on


yes...it is not new technology. Therefore it should be more accurate than 4-5 degrees off...


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## Arcticat (Feb 16, 2012)

Thanks for the above imput, my temp reading is of course off more on hot days. On 90 degree days its at least 4 to 6 degrees higher then the actual outdoor temp.


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## UpstateNYBill (Jan 14, 2012)

audog said:


> If the sensor is in the bezel for the fog lights, it only makes sense that it is reading a temp that is closer to the pavement temp than the actual air temp. It would seem that design engineers would also know that pavement gets warmer than the ambient air temp, so why don't the designers calibrate the readings to take this into account? Or maybe move the sensor to a more accurate position?


Just saw this thread. Logically speaking, temperature close to the roadway is going to be more valuable in the wintertime. I want to know when the possibility exists for icing of the roadway. If the designers artificially recalibrated the temp sensors reading to a higher temperature, what would happen in a wintertime situation when the road ices over and your temperature reading says theres no danger of freezing? Can you say lawsuit when someone slides off the road because they thought the temperature was warmer?

Weather stations have guidelines for temperature sensing equipment so that the readings aren't affected by pavement, nearby surfaces, etc. Impossible to follow with a car, you would have to mount the sensor several feet above the car. Just think how a dark colored car absorbs heat compared with a white car.


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## 70AARCUDA (Nov 14, 2010)

...I would guess that the GM engineers had originally "planned" that temperature sensor to work 'with' the traction-control system so that it would automatically come "on" when the sensor/computer "thought" the road would be getting slushy. But, the way it's working NOW, obviously says 'something' in their plan didn't work out.


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## SeanM402 (Aug 8, 2011)

My temp reading seems to be rather accurate.


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## GoldenCruze (Dec 18, 2011)

If it really is about the temperature of the road surface, then an infrared sensor pointed at the surface would be the way to go. Even better, a couple of them with software that would average the readings.


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