Radio/HVAC Communications

WARNING: This page is about a different car, the 2016 Chevrolet Malibu Limited. However, it is still accessible from the selected car via links, so may be relevant.

Fig 1: Radio/HVAC Communication Diagram

Courtesy of GENERAL MOTORS COMPANY

Callout	Component Name
1	Radio Controls
2	Info Display Module
3	Radio
4	HVAC Control Module
5	Data Link Connector
6	HVAC Controls
a	GMLAN
b	Local Interconnect Network-HVAC
c	CAN Graphical Interface
d	Local Interconnect Network-Radio

The radio controls and information display are separate components from the radio. Each component is supplied battery voltage and ground. The radio uses the wake up circuit to control the power state of the display. The radio controls communicate with the info display module through the LIN serial data circuit. Display backlighting dimming level, graphical data and radio control inputs are communicated over the CGI data circuits between the display and the radio.

The HVAC controls are a separate component from the radio controls. HVAC data for controls and status indicators is communicated between the 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.