Schematic Reference: Radio/Audio System Schematics

Connector Reference: Entertainment Connector End Views

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

1. Turn ON the ignition, with the engine ON.
2. Turn ON the blower motor on the maximum speed.
3. Cycle the auto volume control ON and then OFF.

Is a difference in volume heard?

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Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

1. Turn ON the ignition, with the engine OFF.
2. Disconnect the noise compensation microphone.
3. Measure the voltage from the noise compensation microphone supply voltage circuit to the drain wire.

Does the voltage measure near the specified value?

8 V

Go to Step 4

Go to Step 5

Replace the Onstar microphone. Refer to Mobile Telephone Microphone Replacement .

Did you complete the replacement?

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Go to Step 9

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Test the noise compensation microphone supply voltage circuit for an open or short. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 9

Go to Step 6

Test the drain wire circuit for an open or short. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

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Go to Step 9

Go to Step 7

Inspect for poor connections at the amplifier. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

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Go to Step 9

Go to Step 8

Replace the amplifier. Refer to Control Module References .

Did you complete the repair?

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Go to Step 9

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Operate the system in order to verify the repair.

Did you correct the condition?

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System OK

Go to Step 3