GM Service Manual Online
For 1990-2009 cars only

Reduced Volume - One or More Speakers w/o UM8

Step

Action

Yes

No

Schematic Reference: Radio/Audio System Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the radio.
  3. Adjust the radio balance and fade controls to each speaker.

Do all of the speakers operate properly?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn the ignition ON, with the engine OFF.
  2. Adjust the volume level.
  3. Test the appropriate speaker output circuits of the radio for A/C voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did the A/C voltage fluctuate with the audio output?

Go to Step 4

Go to Step 8

4

  1. Turn OFF the ignition
  2. Disconnect the radio.
  3. Test the appropriate speaker output circuits of the radio for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the harness connector of the radio. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

Inspect for poor connections at the harness connector of the appropriate speaker. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

Replace the speaker. Refer to Speaker Replacement Reference .

Did you complete the replacement?

Go to Step 9

--

8

Replace the radio. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2

Reduced Volume - One or More Speakers WUM8

Step

Action

Yes

No

Schematic Reference: Radio/Audio System Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the radio.
  3. Adjust the radio balance and fade controls to each speaker.

Do all of the speakers operate properly?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Turn the ignition ON, with the engine OFF.
  2. Adjust the volume level.
  3. Test the appropriate speaker output circuits of the radio for A/C voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did the A/C voltage fluctuate with the audio output?

Go to Step 4

Go to Step 8

4

  1. Turn OFF the ignition
  2. Disconnect the radio.
  3. Test the appropriate speaker output circuits of the radio for high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 5

5

Inspect for poor connections at the harness connector of the radio. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

6

Inspect for poor connections at the harness connector of the appropriate speaker. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

7

Replace the speaker. Refer to Speaker Replacement Reference .

Did you complete the replacement?

Go to Step 9

--

8

Replace the radio. Refer to Control Module References in Computer/Integrating Systems for replacement, setup, and programming.

Did you complete the replacement?

Go to Step 9

--

9

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 2