I've noticed this problem and just blamed it on the GM electrical gremlins. Thanks for the heads-up and reminder to RTFM!

 

Somewhat unrelated ...can you "cold Boot " the system by disconecting the power supply for a few minutes like you could with some of the previous electronic generations?

 

Mine has no problem reading the outside temperature, usually it's off a couple of degrees. However it changes once on the road, regardless of distance. Reads higher than the outside air actually is. I assume the sensor is in the path of escaping engine heat. I don't worry about it since I'm wearing a jacket if it's cold or the A/C is on if it's hot. If there's snow & ice on the ground, or if I'm sweating; I have an idea what the temperature is. I'd like it better if I could monitor the oil & coolant temperatures rather the outside temperature!

 

There is a coolant temp display on the DIC....

Oil pressure would be nice though.

 

I'll second that!

 

I have a theory as to why Chevy programs the outside temperature to adjust down immediately and why the adjustments up in temperature occur after a bit of time or mileage as described in several posts above.

A function of the DIC is to alert the driver to the possibility of ice on the road. If the temperature sensor in the wheel well was influenced by the engine heat to display something higher than it really was and this in turn influenced the ICE POSSIBLE display and if again the driver healed this incorrect information and thus was involved in a wreck it could come back to haunt the lawyers at GMC.

That is my take.

 

It shouldn't be this difficult to make a thermometer read the outside temperature and display it on the dash instantaneously.

Sad....

 

Try -13 degrees for a starting temp when it didn't even get down to 20 overnight. Have to drive 7 miles before it will begin to go up, then it takes awhile yet. Stuck on neg temp all day the other day with long distance driving and outside 30+. Amazes me that after 2 years of the same problem and up to 2 wks in the shop at a dealer with their GM help line access, that all I got was a memo explaining the 18mph thing. Not happy, but will copy your posts and ask for the sensor at the front fender to be replaced. Thanks bunches.

 

If temp read out was instant, then at every stop light, it would climb reading the heat from the engine compartment. The upscale car models like Caddy and Buick have had this for decades. My 93 Roadmaster wagon did this as well as all the Envoy/Bravada overhead console displays. GM is assuming that more customers would complain about false high reading than ones complaing that it doesn't change while stop and go driving. I beleive there assumption is correct. I've owned a non GM car that every time the vehicle wasn't moving, the temp read out would slowly climb over a hundred degrees and it was reading the heat off the radiator. On another thread about the blazer overhead consoles, I mention that one wire has to be connected to vehicle speed sensor feed. If this wire isn't connected, it will take one temp reading at vehicle start up, but then never change again unti key it turned off and back on. the S series truck as well as 90's B body used a negitive pulse VSS. I don't know what the HHR uses.

Sounds like the older outside temp units were simple and would take a reading with any vehicle movement i.e. any amount of pulse of the negitive signal from VSS. Sounds like GM had to go and overcomplicate the new system with the 18mph min speed before reading, etc.
Wow, I can't believe GM would take something that works fine and screw it up :)

 

can someone show a picture of where these sensors are, I can't find any forum or video that shows this? my dashboard always reads ---'F