OnStar One or More Buttons Inoperative

OnStar One or More Buttons Inoperative

Diagnostic Fault Information

Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview

Circuit/System Description

The OnStar(R) button assembly consists of 3 buttons, Call/Answer, OnStar(R) Call Center and OnStar(R) Emergency. Ten volts is supplied to the button assembly 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 vehicle communication interface module (VCIM) on the keypad signal circuit. Depending upon the voltage range returned, the VCIM is able to identify which button has been pressed.

Circuit/System Verification

Important: Contact the OnStar(R) Call Center first before pressing the emergency button in order to notify them of the test.

Ignition ON, press the OnStar(R) Call buttons one at the time. Verify that all of the OnStar(R) buttons are inoperative.

If the OnStar(R) Call buttons are operative, go to Testing for Intermittent Conditions and Poor Connections. Component Tests and General Diagnostics

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Ignition ON, test for voltage between 9.8 to 10.2 volts between the supply voltage, terminal 6 and ground

• If less than specified values, test the circuit for an open/high resistance, or for a short to ground. If the circuit tests normal, test or replace the VCIM.

• If more than specified values, test the circuit for a short to voltage. If the circuit tests normal, test or replace the VCIM.

3. If the circuit tests normal, test or replace the inside rearview mirror.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Rearview Mirror Replacement
* Control Module References for VCIM replacement, setup, and programming.