Navigation System Components
The navigation system contains the following components:
• The navigation module
• The navigation interface module (NIM)
• The global positioning system (GPS) antenna
These components then integrate and communicate with the following components:
• The infotainment module
• The steering wheel controls
• The body control module (BCM)
• The instrument cluster
Navigation Module
The navigation module is available in 2 different variants. Both are single DIN units designed as external components 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.
Type A Navigation Module
This navigation module features 'Turn by Turn' directions. The navigation module is an optional accessory to low level vehicles fitted with Type A or C infotainment systems. The navigation module transmits 'Turn by Turn' direction symbols to the instrument cluster display, via serial data to the navigation interface module (NIM) before being translated and re-transmitted via GMLAN. The navigation module also sends audible verbal direction to the speakers through the radio/HVAC control via the NIM. Key entries are entered via the steering wheel remote control.
Type B Navigation Module
This navigation module features 'Turn by Turn' directions as well as displaying full map and routing information on the radio/HVAC control display. The navigation module is an optional accessory to high level vehicles fitted with Type D infotainment systems featuring 6.5" colour LCDs. The navigation module transmits 'Turn by Turn' direction symbols to the instrument cluster display, via serial data to the navigation interface module (NIM) before being translated and re-transmitted via GMLAN. The navigation module also sends audible verbal direction to the speakers through the radio/HVAC control via the NIM. Map based navigation routing information is also channelled directly to the radio/HVAC control display from the navigation module. Key entries are entered via the radio/HVAC control fascia. 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.
Navigation Interface Module (NIM)
The navigation interface module (NIM) is used to communicate data between the navigation module and the vehicle body control module (BCM), the instrument cluster and the radio/HVAC control. The illumination signal and ignition signal messages are sent from the BCM to the NIM via GMLAN, the NIM then translates these signals and re-transmits the data to the navigation module. The odometer and reverse signals are also transmitted to the navigation module via the NIM. The NIM also translates and re-transmits the mute signal from the navigation module via serial data to the radio/HVAC control. The NIM is mounted to the inside edge of the instrument panel insulation panel, directly beneath the I/P compartment.
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 attached to the instrument panel (I/P) carrier and can be accessed by removing the I/P centre air outlet grille 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.
• Proximity to high power distribution locations, i.e. sub-stations, power stations.
