OnStar Button LED Inoperative
OnStar Button LED Inoperative
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.
Circuit/System Description
The vehicle communication interface module (VCIM) commands ON the red or green LED by supplying ground to either the keypad red signal circuit or keypad green signal circuit.
Reference Information
Schematic Reference
OnStar Schematics (OnStar Diagrams)
Connector End View Reference
Component Connector End Views (Connector Views)
Description and Operation
OnStar Description and Operation (OnStar Description and Operation)
Electrical Information Reference
* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)
Circuit/System Verification
Ignition ON, With the scan tool command the VCIM to turn on the red and green LED.
If the red or green LED indicators do not illuminate, refer to Circuit/System Testing.
Circuit/System Testing
1. Ignition OFF, disconnect the inside rearview mirror harness connector .
2. Ignition ON, test for 9.2-10.2 volts on the keypad supply voltage circuit terminal 12.
• If less than the specified voltage repair short to ground or open or replace the VCIM.
3. Test for less than 1 ohm between the inside rearview mirror harness connector terminal 8 and ground.
• If greater than specified value repair open or high resistance.
4. Connect a DMM between the inside rearview mirror harness connector terminal 14 and ground. With a scan tool command the green LED ON. Verify 9.2-10.2 volts is present with the green LED commanded ON.
• If 9.2-10.2 volts is present with the green LED is commanded ON, replace the inside rearview mirror.
5. Connect a DMM between the inside rearview mirror harness connector terminal 15 and ground. With a scan tool command the red LED ON. Verify 9.2-10.2 volts is present with the red LED commanded ON.
• If 9.2-10.2 volts is present with the red LED is commanded ON, replace the inside rearview mirror.
6. Disconnect the VCIM harness connector X1.
7. Test for less than 1 volt between the X1 VCIM connector terminal 3 and the inside rearview mirror harness connector terminal 14.
• If more than the specified value repair short to voltage on the keypad green LED signal circuit.
8. Test for less than 1 volt between the X1 VCIM connector terminal 2 and the inside rearview mirror harness connector terminal 15.
• If more than the specified value repair short to voltage on the keypad red LED signal circuit.
9. Test for less than 1 ohm between the X1 VCIM connector terminal 3 and the inside rearview mirror harness connector terminal 14.
• If more than the specified value repair open or high resistance on the keypad green LED signal circuit.
10. Test for less than 1 ohm between the X1 VCIM connector terminal 2 and the inside rearview mirror harness connector terminal 15.
• If more than the specified value repair open or high resistance on the keypad red LED signal circuit.
11. If all circuits test normal, test or replace the VCIM.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Control Module References (Programming and Relearning) for VCIM replacement, setup, and programming
* Inside Rearview Mirror Replacement (Inside Rearview Mirror Replacement)