Outside thermometer way off

[bodenwell]

The outside thermometer in our 2020 Sierra 3500 is way off.  Consistently reads 8-10 degrees too warm.  I replaced the sensor that is in the passenger side mirror but it made no difference.  Dealer looked at it but did nothing but charge me for an hour of labor.  Anyone have any ideas?

[Transient]

1) Wrong subforum.  You might actually get a response of you post in the correct location. 

 

2) It's not a thermometer.  It's a thermistor.  Vehicle manufacturers use thermistors because they're much cheaper than thermometers.  As such, a thermistor is also less accurate.  I have seen a much variance a +/-3°F.  However, I've seen it +20°F warmer when first starting the vehicle because GM typically installs them under the hood at the front of the engine bay.  It then cools down when you start driving and cooler air passes through the grille. 

[Silverado4x4]

You have to take into account the vehicle sitting or driving on asphalt the heat radiating from the asphalt will be much higher than sitting on something other. 

[GMCustomerService]

15 hours ago, bodenwell said:

The outside thermometer in our 2020 Sierra 3500 is way off.  Consistently reads 8-10 degrees too warm.  I replaced the sensor that is in the passenger side mirror but it made no difference.  Dealer looked at it but did nothing but charge me for an hour of labor.  Anyone have any ideas?

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[carkhz316]

17 hours ago, Transient said:

1) Wrong subforum.  You might actually get a response of you post in the correct location. 

Eh, close enough. Similar enough vehicle for a general tech question anyway.

 

 

17 hours ago, Transient said:

2) It's not a thermometer.  It's a thermistor.  Vehicle manufacturers use thermistors because they're much cheaper than thermometers.  As such, a thermistor is also less accurate.  I have seen a much variance a +/-3°F.  However, I've seen it +20°F warmer when first starting the vehicle because GM typically installs them under the hood at the front of the engine bay.  It then cools down when you start driving and cooler air passes through the grille. 

Potato, potato. Its the ambient air temperature sensor which is a glorified thermometer for the truck. Yes its indeed a thermistor type of circuit. The reason it can be warmer when first starting the vehicle is because the programming ignores the temp sensor for [X] amount of time/ distance driven before it updates the data pid. The inverse will occur when the climate shifts from cold to warmer in-between drive cycles, as the temp display will indicate colder than actual for a brief period.

[redwngr]

21 hours ago, bodenwell said:

The outside thermometer in our 2020 Sierra 3500 is way off.  Consistently reads 8-10 degrees too warm.  I replaced the sensor that is in the passenger side mirror but it made no difference.  Dealer looked at it but did nothing but charge me for an hour of labor.  Anyone have any ideas?

Is it a Duramax?