Just put a 06 impala mirror in my 07 impala, it has a compass, and outside air temp plus auto diming and onstar. Everything works but outside air temp. Where is the sensor located?

 

the sensors are usually located between the grill and the radiator.

 

If the car didn't come stock with that option, you will probably have to add the sensor and maybe a harness. If the harness isn't there, you'll more than likely be inserting pins into the connector at the mirror

 

I'll check it out. No it didn't come with that option but i'll bet they only make one harness for impalas. I figured i'd need to buy sensor.