Ambient Sensor
WARNING: This page is about a different car, the 2007 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.
The ambient sensor (1) is attached on the front bumer reinforcement (left side). It detects ambient temperature and converts it into a resistance value which is then input into the unified meter and A/C amp.
Courtesy of NISSAN MOTOR CO., U.S.A.