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 Instructionsprovides an overview of each diagnostic category.
Diagnostic Fault Information
Circuit Description
The OnStar(R) status LEDs are located in the inside rear view 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 Connector End Views By Name
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 Referencesfor scan tool information
Circuit/System Verification
Note: If the green LED is off with the Key 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, command the Green LED ON and OFF with a scan tool while observing the green LED on the A10 inside rear view 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 A10 inside rear view mirror. The red LED should turn ON and OFF when commanded.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the A10 inside rear view mirror.
2. Test for less than 10 Ohms between the appropriate ground circuit terminal listed below and ground:
* Terminal 5 (-UVC)
* Terminal 8 (UVC)
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, command the green LED OFF with a scan tool. Test for less than 1 V between the control circuit terminal listed below and ground:
* Terminal 6 (-UVC)
* Terminal 14 (UVC)
• If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
4. Command the green LED ON with a scan tool. Test for greater than 9 V between the control circuit terminal listed below and ground:
* Terminal 6 (-UVC)
* Terminal 14 (UVC)
• If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
5. Command the red LED OFF with a scan tool. Test for less than 1 V between the control circuit terminal listed below and ground:
* Terminal 7 (-UVC)
* Terminal 15 (UVC)
• If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the K73 telematics communication interface control module.
6. Command the red LED ON with a scan tool. Test for greater than 9 V between the control circuit terminal listed below and ground:
* Terminal 7 (-UVC)
* Terminal 15 (UVC)
• If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K73 telematics communication interface control module.
7. If all circuits test normal, replace the A10 inside rear view mirror.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Inside Rearview Mirror Replacement Inside Rearview Mirror Replacement
* Control Module References Control Module Referencesfor telematics communication interface control module replacement, setup and programming