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Temperature probe in my car

  1. Aug 4, 2005 #1


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    I have a display in my car that registers outside temperature. It seems to be accurate even in the most adverse circumstances, such as when parked in a parking lot in the sun for a long time. I feel the temperature standing there well over the hundreds, yet the temp gauge does not seem to be fooled by this.

    I would think that thermal conduction and radiation of heat in the vicinity of any probe (such as the heat built up inside my car, which apparently can go over 150 degrees, or the heat rising off the pavement all around my car) would make the probe's temperature reading skyrocket.

    How are they designed so that they give accurate readings?
  2. jcsd
  3. Aug 4, 2005 #2


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    What kind of car do you have? I remember back in my days at Honda we actually had problems with ours. I believe that ours were somewhere under the rear bumper. If I remember correctly, there were quite a few claims where the temp would act erratically. I think the secret is in the coding though, and not the design. I remember reading the logic flow for ours, and it was something like even if you were stopped at a light, and heat from the exhaust was pounding down on the sensor, the reading wouldn't change unless that temperature stayed high for an extended period of time. Then, when you actually started moving, the temp drops back to ambient temp and the "counter" resets.
  4. Aug 4, 2005 #3


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    Well, I have a Chrysler 300M, but that shouldn't make a difference.
  5. Aug 4, 2005 #4


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    Usually they are mounted up front to catch the wind. They haven't always been that way though on certain models. Some will not move off of the previous reading unless the vehicle is moving greater than 25 MPH to prevent heat from the engine and radiator from giving false readings.
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