With Telematics System

WARNING: This page is about a different car, the 2018 Nissan Maxima. However, it is still accessible from the selected car via links, so may be relevant.

Microphone is installed on the map lamp assembly.

Courtesy of NISSAN NORTH AMERICA, INC.
The microphone is used for the operation of the NISSANCONNECT ^SM system, hands-free phone communication and voice recognition functions.
Power is supplied from the TCU.
The microphone transmits sound signals to the TCU during operation of the NISSANCONNECT ^SM system, hands-free phone communication and voice recognition.