kali998 - the nav volume may be way low. To access that volume control hit the "gears" button to the left of the display, select System from that menu, then select Volume Settings. The nav guidance volume control should be there. You can also change the nav guidance volume using the radio volume controls when the nav is giving directions (the volume bar at the top of the screen will turn from purple for radio to green for nav - you can also change call volume that way as well, it is blue).
2016 DS HSE, Corris Grey w/Black Pack, Climate Comfort Pack, Driver Assist Pack, Vision Assist, Audio Upgrade, 5+2 seating, Protection Pack, Black Roof Rails