GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2009 🢒 Lucerne 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 Speaker Malfunction

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Amplifier Battery Positive Voltage

1

1

--

--

Amplifier Control

B1287 02

B1287 04

B1287 01

--

Amplifier Ground

--

1

--

--

Antenna 14V switched Supply Voltage

1

1

--

--

Left Front Low Level Audio Signal (+)/Left Front Speaker Signal (+)

B1025 02

2

B1025 01

--

Left Front Low Level Audio Signal (-)/Left Front Speaker Signal (-)

B1025 02

2

B1025 01

--

Right Front Low Level Audio Signal (+)/Right Front Speaker Signal (+)

B1035 02

2

B1035 01

--

Right Front Low Level Audio Signal (-)/Right Front Speaker Signal (-)

B1035 02

2

B1035 01

--

Left Rear Low Level Audio Signal (+)/Left Rear Speaker Signal (+)

B1045 02

2

B1045 01

--

Left Rear Low Level Audio Signal (-)/Left Rear Speaker Signal (-)

B1045 02

2

B1045 01

--

Right Rear Low Level Audio Signal (+)/Right Rear Speaker Signal (+)

B1055 02

2

B1055 01

--

Right Rear Low Level Audio Signal (-)/Right Rear Speaker Signal (-)

B1055 02

2

B1055 01

--

1. Amplifier inoperative/no sound from speakers

2. no or reduced sound from speaker

Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and at the amplifier (if equipped) have a DC bias voltage that is one half of the battery voltage. When using a DMM, each of the audio output channel circuits will measure approximately 6.5V DC. The audio being played on the system is produced by a varying AC voltage that is centered around the DC bias voltage on the same circuit. The AC voltage is what causes the speaker cone to move and produce sound. This voltage will vary depending on what type of audio is being listened to, talk or music, and type of music, as well as the volume setting of the system. Low volume and talk settings will measure around 1V AC and less, where constant music may measure 3V AC and slightly higher.

Diagnostic Aids
    • Improper speaker mounting or loose trim may cause an audible buzz or distortion. Inspect the appropriate speaker and the surrounding interior trim for proper and secure mounting. If the speaker or surrounding interior trim is found to be loose or improperly secured, correctly secure the item.
    • When equipped with an amplifier, it is possible for some individual circuit faults to affect more than one speakers operation. Perform diagnostic tests in the sequence listed to avoid misdiagnosis.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Radio/Audio System Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Without Amplifier

Radio ON, verify clear audio is heard from each audio speaker.

⇒If audio is inoperative from all speakers, replace the radio.
⇒If audio is inoperative from one or more, but not all, speakers or the audio emitted from the speakers is not clear, refer to Speaker Circuit Malfunction - without Amplifier.

With Amplifier

Radio ON, verify clear audio is heard from each audio speaker.

⇒If audio is inoperative from all speakers, refer to Amplifier Circuit Malfunction.
⇒If audio is inoperative from one or more, but not all, speakers or the audio emitted from the speakers is not clear, refer to Speaker Circuit Malfunction - with Amplifier.

Circuit/System Testing

Speaker Circuit Malfunction - without Amplifier

  1. Ignition OFF, disconnect the harness connector at the appropriate speaker.
  2. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.
    3. ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  3. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.
    4. ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  4. If all circuits test normal, replace the appropriate speaker.

Amplifier Circuit Malfunction

  1. Ignition OFF, disconnect the X1 harness connector at the amplifier.
  2. Test for less than 10 ohms of resistance between the ground circuit terminal 4 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 8 and ground.
    4. ⇒If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the circuit fuse is open, replace the amplifier.
  4. Disconnect the X3 harness connector at the amplifier.
  5. Radio ON, test for 0.5-1.0 volts between the signal circuit terminal 6 and ground.
    6. ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  6. Verify a test lamp illuminates between the signal circuit terminal 13 and ground.
    7. ⇒If the test lamp does not illuminate, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  7. If all circuits test normal, replace the amplifier.

Speaker Circuit Malfunction with Amplifier

  1. Ignition OFF, disconnect the X3 harness connector at the amplifier.
  2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    3. • Left front low level audio signal (-) - terminal 1
    • Left front low level audio signal (+) - terminal 9
    • Right front low level audio signal (-) - terminal 2
    • Right front low level audio signal (+) - terminal 10
    • Left rear low level audio signal (-) - terminal 3
    • Left rear low level audio signal (+) - terminal 11
    • Right rear low level audio signal (-) - terminal 4
    • Right rear low level audio signal (+) - terminal 12
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio.
  3. Ignition OFF, disconnect the X1 and X2 harness connectors at the amplifier.
  4. Ignition ON, test for less than 1 volt between each of the signal circuit terminals listed below and ground.
    5. • Left rear shelf speaker output (-) - terminal 2 X1
    • Left rear shelf speaker output (+) - terminal 6 X1
    • Right rear shelf speaker output (-) - terminal 3 X1
    • Right rear shelf speaker output (+) - terminal 7 X1
    • Front center speaker output (-) - terminal 6 X2
    • Front center speaker output (+) - terminal 14 X2
    • Left front speaker output (-) - terminal 2 X2
    • Left front speaker output (+) - terminal 10 X2
    • Right front speaker output (-) - terminal 3 X2
    • Right front speaker output (+) - terminal 11 X2
    • Left rear door speaker output (-) - terminal 4 X2
    • Left rear door speaker output (+) - terminal 12 X2
    • Right rear door speaker output (-) - terminal 5 X2
    • Right rear door speaker output (+) - terminal 13 X2
    ⇒If greater than the specified range, test both signal circuits of the affected speaker for a short to voltage.
  5. Ignition OFF, test for infinite resistance between each of the signal circuit terminals listed below and ground.
    6. • Left rear shelf speaker output (-) - terminal 2 X1
    • Left rear shelf speaker output (+) - terminal 6 X1
    • Right rear shelf speaker output (-) - terminal 3 X1
    • Right rear shelf speaker output (+) - terminal 7 X1
    • Front center speaker output (-) - terminal 6 X2
    • Front center speaker output (+) - terminal 14 X2
    • Left front speaker output (-) - terminal 2 X2
    • Left front speaker output (+) - terminal 10 X2
    • Right front speaker output (-) - terminal 3 X2
    • Right front speaker output (+) - terminal 11 X2
    • Left rear door speaker output (-) - terminal 4 X2
    • Left rear door speaker output (+) - terminal 12 X2
    • Right rear door speaker output (-) - terminal 5 X2
    • Right rear door speaker output (+) - terminal 13 X2
    ⇒If less than the specified range, test both signal circuits of the affected speaker for a short to ground.
  6. Reconnect all harness connectors at the amplifier. Disconnect the harness connector at the appropriate speaker.
  7. Radio ON, test for 5.0-7.5 volts between each of the appropriate signal circuit terminals listed below and ground.
    8. • Center IP speaker - terminals A and B
    • Door speakers - terminals A and B
    • Front tweeter speakers - terminals A and B
    • Rear shelf speakers - terminals A and B
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the audio amplifier.
    ⇒If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the audio amplifier.
  8. If all circuits test normal, replace the appropriate speaker.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Speaker Replacement Reference
    •  Control Module References for audio amplifier or radio replacement, setup, and programming