Info button on NAV

[Cy in NC]

What does this button do? When I push it screen with NAV Min shows up. You can then adjust something (I don't know what) by +9 through -9. :dunno:

[man02195]

With the "Nav-Min" function you set a minimum volume for the audio driving
instructions.
1. Enter the selection menu
2. Use the right-hand rotary button to select "Nav-Min". A selection menu appears on the screen
3. Select "Nav-Min +" or "Nav-Min -"
4. Press the right-hand rotary button repeatedly until the desired volume is set. You can select a step between -9 and +9; step 0 is equal to a moderate volume. The selected minimum volume is maintained for all audio driving instructions.

[Cy in NC]

that is what I thought it might be for but I could not distinguish any difference in the NAV volume compaired to the radio. Does this setting override the NAV volume settings in the Setting menu?