OnStar® Button Assembly

WARNING: This page is about a different car, the 2002 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.

The OnStar® button assembly may be part of the rear view mirror on some vehicles and a separate unit on others. The button assembly is comprised of the 3 buttons and a status LED. The buttons are as follows:

The button with a "dot" when pressed allows the user to answer/end calls.
The OnStar® Call Center button, with the OnStar® logo, when pressed connects the user to the OnStar® call center.
The red Emergency button when pressed sends a high priority/emergency call to the OnStar® call center.

The OnStar® button assembly receives ten volts on the keypad supply voltage circuit. Each of the buttons when pressed, completes the circuit across a resister allowing a specific voltage to be returned to the VIU on the keypad low reference circuit. Depending the voltage range returned, the VIU is able to identify which button has been pressed.

The OnStar® button assembly status LED is green when the system is on and operating normally. When the status LED is green and flashing, this means a call is in progress. When the LED is red, this indicates a system malfunction is present. The OnStar® LED is controlled by the VIU over the keypad LED red signal circuit and the keypad LED green signal circuit.