Schematic Reference: OnStar Schematics

Connector End View Reference: Cellular Communication Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

Verify the talk button is inoperative.

Does the talk button operate normally?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

1. Turn the ignition ON with the engine OFF.
2. With a scan tool, observe the Talk Button Switch data parameter in the body control module (BCM) data list.
3. Depress the Talk Button Switch

Does the scan tool display change from Inactive to Active?

Go to Step 8

Go to Step 4

1. Disconnect the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement.
2. Place a fused jumper between the headlamp switch headlamps on signal circuit and low reference circuit terminals.

Does the scan tool change from Inactive to Active?

Go to Step 6

Go to Step 5

Test for one of the following conditions in the headlamp and panel dimmer switch circuits. Refer to Circuit Testing and Wiring Repairs.

Go to Step 9

Go to Step 7

Inspect for poor connections at the harness connector of the headlamp and panel dimmer switch. Refer to Circuit Testing and Wiring Repairs.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

Replace the headlamp and panel dimmer switch. Refer to Headlamp Switch Replacement.

Did you complete the repair?

Go to Step 9

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

Did you complete the replacement?

Go to Step 9

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1. Use the scan tool in order to clear any induced DTCs.
2. Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2