Temp. on mirror is wrong!

[OFF-RD]

On my new truck, the temperature that shows up in the corner of the mirror is wrong. It consistently reads about 5 degrees too warm. I checked it with the truck OFF and the engine COOL so it's not picking up heat from the engine. It's just not accurate. What could be the problem? Could the sensor itself be the problem? Or is it in the wiring? Or the BCM?

[superbee]

My 'Burban had the same problem, it was the sensor.

[Rolandd]

Check in the morning before the sun is heating the road under the truck. The sensor is under the front bumber and can pick up heat radiating up from the road.

[pm26]

Seems like a pretty insignificant "problem" to me. This GM truck is the first vehicle I have ever owned with an outside temperature display. How did I ever manage to get by without it?

[OFF-RD]

Well, considering that 5 degrees can mean the difference between sliding off the road in a crash and staying in your lane...I'd say it's not an insignifcant problem. If the feature is going to be on the truck...then it needs to work properly.

 

Now, this morning before the sun came up I walked out to the truck and checked it...once again 5 degrees too warm. So I guess I'll get with the dealership and see if they'll replace the sensor under warranty. I'll try that first.

[Wingnut]

Just curious, but what are you using as a reference for ambient temperature in order to see the discrepancy?

[superbee]

Man, do you guys work at my stealership? You sure sound like it, "can't duplicate" "not significant" "they all do that". All crap, these trucks are too expensive for this stuff not to work, especially under warranty.

[jhm]

Well, considering that 5 degrees can mean the difference between sliding off the road in a crash and staying in your lane...I'd say it's not an insignifcant problem.  If the feature is going to be on the truck...then it needs to work properly.

 

Now, this morning before the sun came up I walked out to the truck and checked it...once again 5 degrees too warm.  So I guess I'll get with the dealership and see if they'll replace the sensor under warranty.  I'll try that first.

 

<{POST_SNAPBACK}>

 

 

Holy crap batman. Are you saying you rely on a cheap made in taiwan thermometer to decide how you should drive?

[pwall]

Yep...sounds like it to me.

Up here in the cold North, if the display doesn't say ICE, then there can't be any. ;)

[95Sierra2500]

If you go look at thermometers at wal-mart/home depot/anywhere else, I'll bet there's a good 5 degree discrepancy between ALL of them. It's the same on cars. My GTP and my fiancee`'s Jimmy both have an outside temp. display, and they're both 2-5 degrees high depending on conditions (usually about 2). It IS normal for a thermometer to be off a few degrees, even as high as 5. That's why (at least on her Jimmy) any time it's below 38 degrees it warns that ice is possible...

[jhm]

Yep...sounds like it to me.

Up here in the cold North, if the display doesn't say ICE, then there can't be any.  ;)

 

<{POST_SNAPBACK}>

 

 

We get "black ice" here anytime from Oct to Apr. You can be driving on perfectly dry pavement then hit a spot with the black ice and suddenly you are totally out of control. I really think those thermometers are just basic reference gages, not to be taken seriously.

[Frozen001]

This is why people do not know how to drive... If you are relying on that gauge to decide how to drive you really should not be driving. to me 5 degrees is not that much...to tell you the truth I do not even thing I use the reading for much at all... it was included with the package so it is there... I would not have actually selected it if it was a separate option. Hell when I put my plow on the reading gets really weird... it will be snowing like crazy and it reads like 60 degrees...does that mean it should be raining

 

In all honestly the temp gauge is based off of a thermocouple which has a different resistance depending on what the temperature is. So if GM switched suppliers and did not re-program the gauge, then it is very possible that they are off. Hell even variations in the production of the thermocouples will cause errors of a few degrees unless the gauge is calibrated, and I am sure GM does and will not calibrate each vehicle that has one... as long as it is +/- a few degrees they do not really care.

[redvett]

On my new truck, the temperature that shows up in the corner of the mirror is wrong.  It consistently reads about 5 degrees too warm.  I checked it with the truck OFF and the engine COOL so it's not picking up heat from the engine.  It's just not accurate.  What could be the problem?  Could the sensor itself be the problem?  Or is it in the wiring?  Or the BCM? 

 

<{POST_SNAPBACK}>

 

 

 

You must be moving and have driven at least 1 mile to get a accurate reading.

[jhm]

On my new truck, the temperature that shows up in the corner of the mirror is wrong.  It consistently reads about 5 degrees too warm.  I checked it with the truck OFF and the engine COOL so it's not picking up heat from the engine.  It's just not accurate.  What could be the problem?  Could the sensor itself be the problem?  Or is it in the wiring?  Or the BCM?  

 

<{POST_SNAPBACK}>

 

 

 

You must be moving and have driven at least 1 mile to get a accurate reading.

 

<{POST_SNAPBACK}>

 

 

 

Why would that have anything to do with the accuracy?

[SoCalChris]

GM-Tech had posted a while ago a description of how the temp sensor came up with it's reading. It was actually far more complex than I thought it would be, and makes adjustments based on how long the car has been driving (To compensate for the heat coming from the radiator). If I remember right, it actually takes about 10 minutes for the thermometer to go through its startup cycle.

 

edit:

Found the post I was reffering to

http://www.gm-trucks.com/forums/index.php?...&hl=thermometer