The numbers below refer to the step numbers on the diagnostic table.
Determines if the OnStar® status LED has the necessary GREEN LED signal circuit voltage.
If the GREEN LED signal is shorted to voltage then the OnStar® 3-button assembly has been damaged and the OnStar® 3-button assembly must be replaced.
Step  | Action  | Value(s)  | Yes  | No  | 
|---|---|---|---|---|
Schematic Reference: OnStar Schematics Connector End View Reference: Component Connector End Views DEFINITION: This procedure is for diagnosing problems with the OnStar® button assembly LED.  | ||||
1  | Did you perform the Diagnostic System Check - Vehicle?  | --  | Go to Step 2  | |
2  | 
 Did the OnStar® status LED turn GREEN?  | --  | Go to Testing for Intermittent Conditions and Poor Connections and Connector Repairs  | Go to Step 3  | 
Measure the voltage from the keypad GREEN LED signal circuit to a good ground. Does the voltage measure near the specified value?  | 7 V  | Go to Step 6  | Go to Step 4  | |
4  | Test the keypad GREEN LED signal circuit for an open, high resistance or a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 10  | Go to Step 5  | 
Test the keypad GREEN LED signal circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition?  | --  | Go to Step 7  | Go to Step 8  | |
6  | Inspect for poor connections at the harness connector of the rearview mirror. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?  | --  | Go to Step 10  | Go to Step 7  | 
7  | Replace the rearview mirror. Refer to Inside Rearview Mirror Replacement . Did you complete the repair?  | --  | Go to Step 10  | --  | 
8  | Inspect for poor connections at the harness connector of the vehicle communication interface module (VCIM). Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition?  | --  | Go to Step 10  | Go to Step 9  | 
9  | 
 Important: Perform the OnStar® setup procedure. Replace the VCIM. Refer to Control Module References . Did you complete the repair?  | --  | Go to Step 10  | --  | 
10  | Operate the system in order to verify the repair. Did you correct the condition?  | --  | System OK  | Go to Step 2  |