The ambient temperature sensor is in the bumper cover on my 2011, like this

 

Here it is on my 09, from when I replaced the intercooler and headlights. Just like the diagram donbrew posted.

 

Looks like some tire rub there on the inner fender.
I wonder why the SS has the sensor over on the passenger side and the LT has it in the driver’s side?

 

Yes, I forgot to fasten it back one time. I've since put a new one on.

Where do you see it on the driver side?

 

2010 & 2011 are on driver side.

 

here on the bumper cover

 

Has the Black Swan had the bumper replaced or painted? Why is it red? Maybe that's not your pic?

 

It’s not a picture of my HHR just a file photo from the interwebs!

 

That's where they are for 2010-2011. "Hanging around the radiator."

 

Well I pulled the cover, installed the fogs since I couldnt get them to snap in from the well, the bumper has a sensor mounted on the drivers side (no wire to connect ) so guess this is a newer year cover? anyways, got the sensor mounted to the frame, fogs in and markers hooked up but 3 of the 4 bulbs are out, ordering new 194LL marker bulbs now (LL is long life) tried to pop the airbag out but couldnt get it to come loose through the holes? anyways, try another day, its already 100 outside.