Control Module Connection Via CAN

Function
All control modules with a control function for the automatic air conditioning are connected with one another by the passenger compartment bus (CAN class B). The CAN data bus is a bidirectional bus, i.e, each control module connected is capable of transmitting and receiving information.
A defined data protocol specifies how and when the control modules can transmit and receive information. The CAN data bus has a message-related address system.
This means that each message is assigned a fixed address (identifier), indicating the contents of the message. The receiver evaluates only the messages (data telegrams) stored in its list of messages to be received (acceptancy check).

Communication for temperature control between automatic A/C pushbutton control module and rear A/C pushbutton control module
The automatic A/C pushbutton control module reads all values set on the rear A/C pushbutton control module in the passenger compartment bus (CAN class B) and calculates internally the required outlet temperatures for the, entire passenger compartment. The values calculated for the left and right rear transferred to the rear A/C pushbutton control module via the passenger compartment bus (CAN class B). The rear A/C pushbutton control module regulates its outlet temperatures itself.