GM Service Manual Online
For 1990-2009 cars only

Navigation System Components

The navigation system contains the following components:

    • The navigation module
    • The global positioning system (GPS) antenna
    • The accessory switch

These components then integrate and communicate with the following components:

    • The infotainment unit
    • The body control module (BCM)

Navigation Module

The navigation module is a single DIN unit designed as an external component which can be installed as part of the infotainment system. The navigation module is mounted in the instrument panel compartment and contains all the navigation engines and gyroscope used to detect movement of the vehicle.

The navigation module features 'Turn by Turn' directions as well as displaying full map and routing information on the infotainment unit display. The navigation module is an optional accessory to vehicles fitted with Type E or F infotainment units featuring 6.5" colour LCDs. The navigation module transmits 'Turn by Turn' direction symbols to the instrument cluster display, via serial data to the NIM before being translated and re-transmitted via GMLAN. The navigation module also sends audible verbal direction to the speakers through the infotainment unit via the interface module. Map based navigation routing information is also channelled directly to the infotainment unit display from the navigation module. Key entries are entered via the control switch in the centre console. The INFO button on the steering wheel is used to recall the last audible direction, and also displays the function on the instrument clusters centre multi-function display.

Refer to the owner literature for detailed description.

Global Positioning System (GPS) Antenna

The global positioning system (GPS) locates the current position of the vehicle using signals sent by GPS satellites. The GPS antenna is located within the roof mounted shark fin antenna assembly. The GPS antenna is powered through the same coaxial cable used to send the signals to the navigation module. Interference to the system may occur if any of the following exist:

    • Signal shadowing, when signals are obstructed by objects such as tall trees or buildings.
    • Metallic objects located on the dashboard.
    • Aftermarket glass tinting has been applied to the vehicles windshield.
    • Ionospheric disturbance (caused by solar activity, which results in greatly increased radio wave absorption).
    • Atmospheric disturbances caused by stormy weather.