OnStar Button LED Malfunction
OnStar Button LED Malfunction
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit Description
The OnStar(R) status LEDs are located in the inside rearview mirror telematic button 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 telematics communication interface control module via the keypad green LED control circuit and the keypad red LED control circuit.
Reference Information
Schematic Reference
OnStar Schematics OnStar Schematics
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation
OnStar Description and Operation OnStar
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
Note: If the green LED is off with the ignition ON and the LED functions correctly when commanded with the scan tool, contact the OnStar Center to confirm the vehicle has a current subscription.
1. Ignition ON.
2. Verify that the green LED turns ON and OFF when commanding the K73 telematics communication interface control module green indicator ON and OFF with a scan tool.
• If the green LED does not turn ON and OFF
Refer to Circuit/System Testing - Green LED Test
• If the green LED turns ON and OFF
3. Verify that the red LED turns ON and OFF when commanding the K73 telematics communication interface control module red indicator ON and OFF with a scan tool.
• If the red LED does not turn ON and OFF
Refer to Circuit/System Testing - Red LED Test
• If the red LED turns ON and OFF
4. All OK.
Circuit/System Testing
Green LED Test
1. Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the A10 inside rearview mirror. It may take up to 2 minutes for all vehicle systems to power down. Doors closed, courtesy lamps OFF.
2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Test for less than 1 V between the control circuit terminal 6 and ground while commanding the K73 telematics communication interface control module green indicator OFF with a scan tool.
• If 1 V or greater
1. Ignition OFF, disconnect the X1 harness connector at the K73 telematics communication interface control module, ignition ON.
2. Test for less than 1 V between the control circuit terminal 6 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K73 telematics communication interface control module.
• If less than 1 V
5. Test for greater than 8 V between the control circuit terminal 6 and ground while commanding the K73 telematics communication interface control module green indicator ON with a scan tool.
• If 8 V or less
1. Ignition OFF, disconnect the X1 harness connector at the K73 telematics communication interface control module.
2. Test for infinite resistance between the control circuit terminal 6 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K73 telematics communication interface control module.
• If greater than 8 V
6. Test or replace the A10 inside rearview mirror.
Red LED Test
1. Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the A10 inside rearview mirror. It may take up to 2 minutes for all vehicle systems to power down. Doors closed, courtesy lamps OFF.
2. Test for less than 10 ohms between the ground circuit terminal 5 and ground.
• If 10 ohms or greater
1. Ignition OFF.
2. Test for less than 2 ohms in the ground circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, repair the open/high resistance in the ground connection.
• If less than 10 ohms
3. Ignition ON.
4. Test for less than 1 V between the control circuit terminal 7 and ground while commanding the K73 telematics communication interface control module red indicator OFF with a scan tool.
• If 1 V or greater
1. Ignition OFF, disconnect the X1 harness connector at the K73 telematics communication interface control module, ignition ON.
2. Test for less than 1 V between the control circuit terminal 7 and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the K73 telematics communication interface control module.
• If less than 1 V
5. Test for greater than 8 V between the control circuit terminal 7 and ground while commanding the K73 telematics communication interface control module red indicator ON with a scan tool.
• If 8 V or less
1. Ignition OFF, disconnect the X1 harness connector at the K73 telematics communication interface control module.
2. Test for infinite resistance between the control circuit terminal 7 and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms in the control circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the K73 telematics communication interface control module.
• If greater than 8 V
6. Test or replace the A10 inside rearview mirror.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Inside Rearview Mirror Replacement Inside Rearview Mirror Replacement
* Control Module References Control Module References for telematics communication interface control module replacement, programming and setup.