Radio/HVAC Controls

WARNING: This page is about a different car, the 2010 Cadillac SRX. However, it is still accessible from the selected car via links, so may be relevant.

The radio/HVAC controls is a separate component from the radio. The radio/HVAC controls contain the radio control knobs and buttons for all audio functions.

The radio/HVAC controls operate radio functions through serial data messages. The radio/HVAC controls communicate to the info display module through LIN serial data. The info display module communicates to radio through CGI serial data.

When equipped with the optional navigation radio, the radio/HVAC controls communicate directly to the navigation radio, and the display communicates information through the signal circuits to the navigation radio.

When the operator rotates a radio control knob to change radio stations or increase the volume a message is sent to the radio over serial data. After receiving the message the radio will make the adjustment. Messages communicated between the radio and the radio/HVAC controls and info display include the following:

Button presses/knob rotations
Info display module dimming
Radio/HVAC controls back-lighting
Graphics and text information

HVAC data for controls and status indicators is communicated between the radio/HVAC controls and the HVAC control module with a separate LIN serial data circuit. HVAC status screen information from the HVAC control module is transmitted to the radio on the GMLAN serial data circuit. The radio then displays the desired screen information on the info display using the video data circuits.