For 1990-2009 cars

#### Test Description

The numbers below refer to the step numbers on the diagnostic table.

1. This step determines if the OnStar® status LED has the necessary GREEN LED signal circuit voltage.

2. If the GREEN LED signal is shorted to voltage, then the OnStar® 3-button assembly has been damaged and must be replaced.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Schematic Reference: OnStar Schematics Connector End View Reference: Entertainment/Communication 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 | Go to Diagnostic System Check - Vehicle
2 |

1. Turn the ignition ON, with engine OFF.
2. Observe the OnStar® status LED.

Did the OnStar® status LED turn GREEN?

--

Go to Testing for Intermittent Conditions and Poor Connections and Connector Repairs

Go to Step 3

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
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 | Replace the VCIM. Refer to Control Module References for replacement, setup, and programming. 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