04
*02
GA-Net Bus Configuration
Charge Signal and Navigation Unit Cooling Fan Operation
23-78
Navigation System
System Description (cont’d)
Audio Unit
Accessory (MP3
player, Cassette etc.)
Navigation
Control Unit
Navigation
Display
XM Receiver
CD Changer
FAN CONTROL
LOGIC
ECM/PCM
The GA-Net bus passes audio and navigation commands throughout the navigation and audio components.
These commands include navigation touch screen and hard button signals, audio/XM selections by voice, and XM
station and music title names. Because the entire bus is ‘‘daisy chained’’ between components (see diagram below),
any open or short in the GA-Net bus harness will cause any or all of these functions to become inoperative. The
addition of any factory audio accessory must maintain the continuity of the GA-Net bus by installing the ‘‘Y’’ cable
included with the accessory kit.
The ECM/PCM sends a charge signal to the navigation unit via F-CAN. A thermister inside the navigation unit monitors
the units internal temperature. This information combined with charge signal determines the control units internal
cooling fan operation.