Heated Seat Operation
WARNING: This page is about a different car, the 2008 Cadillac CTS. However, it is still accessible from the selected car via links, so may be relevant.
The driver and passenger heated seats are controlled by separate heated seat switches. Both switches are located in the CCP. When a heated seat switch is pressed, the CCP sends a class 2 message via the serial data line to the memory seat module (MSM) indicating the heated seat command. In response to this signal, the MSM then applies or removes battery voltage through the element supply voltage circuit of the seat heating elements. The MSM then sends a class 2 message back to the CCP to either illuminate or turn off the appropriate temperature indicator.