Other Inputs

The navigation unit also monitors:

The illumination circuit signal - When the headlights are turned on, the navigation unit detects 12 volts on the illumination circuit and switches to night mode (with the display set on auto illumination).

The reverse (BACK UP) signal - Because the vehicle speed signal is a digital signal and is not directional, it can only be used to determine the speed of the vehicle, not the direction of travel. Because of this limitation, the navigation unit monitors the BACK UP signal from the reverse relay when the transmission is placed in reverse. When the navigation unit detects 12 volts on the BACK UP circuit, it shows the icon on the map moving in a reverse direction. The BACK UP signal is also used to tell the navigation system to display the optional rear view camera.

The charge circuit signal - To prevent the navigation system from depleting the battery, the navigation system will shut down if the charge system is not operating properly, or the engine is not running. When the alternator is operating normally, it applies 12 volts to the charge indicator circuit. When the navigation unit detects 12 volts on the charge indicator circuit it will keep the navigation in the normal mode. If the navigation unit detects 0 volts on the charge indicator circuit, the navigation system will shut down after about 5 minutes.