OnStar Button LED Inoperative

OnStar Button LED Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit Description

The OnStar(R) status LEDs are located to the right of the emergency button on the inside rearview mirror assembly. The green LED is illuminated when the system is ON and operating normally. When the green LED is green and flashing, it is an indication that a call is in progress. When the red LED is illuminated, a system malfunction is present. In the event there is a system malfunction and the OnStar(R) system is still able to make a call, the LED will flash red during the call. The OnStar(R) LEDs are controlled by the vehicle communication interface module (VCIM) via the keypad green LED signal circuit and the keypad red LED signal circuit.

Circuit/System Verification

1. Ignition ON, command the Green LED ON and OFF with a scan tool while observing the green LED on the inside rearview mirror. The green LED should turn ON and OFF when commanded.
2. Command the red LED ON and OFF with a scan tool while observing the red LED on the inside rearview mirror. The red LED should turn ON and OFF when commanded.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Ignition OFF, doors closed, interior lamps OFF, test for less than 5 ohms between the inside rearview mirror ground circuit terminal 8 and ground.

^ If greater than specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, command the appropriate LED OFF with a scan tool. Test for less than 1 volt between the appropriate LED signal circuit terminal and ground.

^ If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the VCIM.

4. Command the appropriate LED ON with a scan tool. Test for greater than 9 volts between the appropriate LED signal circuit terminal and ground.

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

5. If all circuits test normal, replace the inside rearview mirror.

Repair Instructions

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

* Inside Rearview Mirror Replacement