Circuit/System Description
WARNING: This page is about a different car, the 2018 Cadillac XT5. However, it is still accessible from the selected car via links, so may be relevant.
The telematics communication interface button assembly consists of 2 buttons: Emergency (SOS) button and the TEST button. The telematics communication interface control module supplies the button assembly with 10 V via the 10 V reference circuit. Each of the buttons, when pressed, completes the circuit across a resistor allowing a specific voltage to be returned to the telematics communication interface control module over the keypad signal circuit. Depending upon the voltage range returned, the telematics communication interface control module is able to identify which button has been pressed.