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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2007 🢒 Sierra - 2WD 🢒 Driver Information and Entertainment 🢒 Cellular, Entertainment, and Navigation 🢒 Speakers Inoperative - One or More

Speakers Inoperative - One or More new

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 provide an overview of each diagnostic category.

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

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

B1025 02, *

1

B1025 01, *

--

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

B1025 02, *

1

B1025 01, *

--

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

B1035 02, *

1

B1035 01, *

--

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

B1035 02, *

1

B1035 01, *

--

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

B1045 02, *

1

B1045 01, *

--

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

B1045 02, *

1

B1045 01, *

--

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

B1055 02, *

1

B1055 01, *

--

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

B1055 02, *

1

B1055 01, *

--

1. No or reduced audio

* Noticeable audio distortion possible.

Circuit/System Description

Each of the audio output channel circuits (+) and (-), at the radio and audio amplifier 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.
    • The front tweeter speakers are connected to the same channel as the front door speakers.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Entertainment/Communication 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

Scan Tool Data List for scan tool information

Circuit/System Verification

Radio ON, Rear Seat Audio (RSA) OFF (if equipped), adjust the fade and balance controls on the radio to test all four channels individually. Each of the four channels should produce clear and even sound.

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 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.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. 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 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.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  4. If all circuits test normal, replace the speaker.

Amplifier Circuit Malfunction

  1. Ignition OFF, disconnect the C1 harness connector at the audio amplifier.
  2. Ignition OFF, test for less than 1 volt between the ground circuit terminal 8 and ground.
    3. ⇒If greater than the specified range, test the ground circuit for an short to voltage.
  3. Ignition OFF, test for less than 10 ohms between the ground circuit terminal 8 and ground.
    4. ⇒If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, test for B+ between the B+ circuit terminal 4 and ground.
    5. ⇒If less then specified value, test the circuit for a short to ground, or an open/high resistance.
  5. Ignition OFF, disconnect the C3 harness connector at the audio amplifier.
  6. For vehicles without RPO code Y91 only: Radio ON, test for B+ between the amplifier control circuit terminal 11 and ground.
    7. ⇒If less than the specified range, test the control 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 audio amplifier.

Speaker Malfunction Radio Output Testing (-Y91) (-U42)

  1. Ignition OFF, disconnect the C3 connector at the amplifier.
  2. Ignition ON, 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 15
    • Left front low level audio signal (-) - terminal 7
    • Right front low level audio signal (+) - terminal 14
    • Right front low level audio signal (-) - terminal 6
    • Left rear low level audio signal (+) - terminal 13
    • Left rear low level audio signal (-) - terminal 5
    • Right rear low level audio signal (+) - terminal 12
    • Right rear low level audio signal (-) - terminal 4
    ⇒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.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. If all circuits test normal, replace the amplifier.

Speaker Malfunction Radio Output Testing (-Y91) (+U42)

  1. Ignition OFF, disconnect the C3 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 15
    • Left front low level audio signal (-) - terminal 7
    • Right front low level audio signal (+) - terminal 14
    • Right front low level audio signal (-) - terminal 6
    ⇒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.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. Ignition OFF, reconnect the C3 harness connector at the amplifier.
  4. Disconnect the C2 harness connector at the rear seat audio (RSA) module.
  5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    6. • Left rear low level audio signal (+) - terminal 1
    • Left rear low level audio signal (-) - terminal 2
    • Right rear low level audio signal (+) - terminal 3
    • Right rear low level audio signal (-) - terminal 4
    ⇒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 rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  6. Ignition OFF, reconnect the C2 harness connector at the rear seat audio (RSA) module.
  7. Disconnect the C3 harness connector at the amplifier.
  8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    9. • Left rear low level audio signal (+) - terminal 13
    • Left rear low level audio signal (-) - terminal 5
    • Right rear low level audio signal (+) - terminal 12
    • Right rear low level audio signal (-) - terminal 4
    ⇒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 rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  9. If all circuits test normal, replace the amplifier.

Speaker Malfunction Radio Output Testing (+Y91) (-U42)

  1. Ignition OFF, disconnect the C2 and C3 harness connectors 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 11 C3
    • Left front low level audio signal (-) - terminal 12 C3
    • Right front low level audio signal (+) - terminal 3 C3
    • Right front low level audio signal (-) - terminal 4 C3
    • Left rear low level audio signal (+) - terminal 15 C2
    • Left rear low level audio signal (-) - terminal 14 C2
    • Right rear low level audio signal (+) - terminal 16 C2
    • Right rear low level audio signal (-) - terminal 8 C2
    ⇒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.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. If all circuits test normal, replace the amplifier.

Speaker Malfunction Radio Output Testing (+Y91) (+U42)

  1. Ignition OFF, disconnect the C3 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 11
    • Left front low level audio signal (-) - terminal 12
    • Right front low level audio signal (+) - terminal 3
    • Right front low level audio signal (-) - terminal 4
    ⇒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.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio.
  3. Ignition OFF, reconnect the C3 harness connector at the amplifier.
  4. Disconnect the C2 harness connector at the rear seat audio (RSA) module.
  5. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    6. • Left rear low level audio signal (+) - terminal 1
    • Left rear low level audio signal (-) - terminal 2
    • Right rear low level audio signal (+) - terminal 3
    • Right rear low level audio signal (-) - terminal 4
    ⇒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 rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  6. Ignition OFF, reconnect the C2 harness connector at the rear seat audio (RSA) module.
  7. Disconnect the C2 harness connector at the amplifier.
  8. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground.
    9. • Left rear low level audio signal (+) - terminal 15 C2
    • Left rear low level audio signal (-) - terminal 14 C2
    • Right rear low level audio signal (+) - terminal 16 C2
    • Right rear low level audio signal (-) - terminal 8 C2
    ⇒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 rear seat audio (RSA) module.
    ⇒If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the rear seat audio (RSA) module.
  9. If all circuits test normal, replace the amplifier.

Speaker Malfunction Amplifier Output Testing (-Y91)

  1. Ignition OFF, disconnect the C1 and C2 connectors at the amplifier.
  2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground:
    3. • Left front speaker output (+) - terminal 4 C2
    • Left front speaker output (-) - terminal 3 C2
    • Right front speaker output (+) - terminal 2 C2
    • Right front low speaker output (-) - terminal 1 C2
    • Left rear speaker output (+) - terminal 8 C2
    • Left rear speaker output (-) - terminal 7 C2
    • Right rear speaker output (+) - terminal 6 C2
    • Right rear speaker output (-) - terminal 5 C2
    • Left subwoofer speaker output (+) - terminal 7 C1
    • Left subwoofer speaker output (-) - terminal 3 C1
    • Right subwoofer speaker output (+) - terminal 6 C1
    • Right subwoofer speaker output (-) - terminal 2 C1
    ⇒If greater than the specified range, test both circuits of the affected speaker for a short to voltage.
  3. Radio OFF, test for infinite resistance between the appropriate signal circuit terminal listed below and ground:
    4. • Left front speaker output (+) - terminal 4 C2
    • Left front speaker output (-) - terminal 3 C2
    • Right front speaker output (+) - terminal 2 C2
    • Right front low speaker output (-) - terminal 1 C2
    • Left rear speaker output (+) - terminal 8 C2
    • Left rear speaker output (-) - terminal 7 C2
    • Right rear speaker output (+) - terminal 6 C2
    • Right rear speaker output (-) - terminal 5 C2
    • Left subwoofer speaker output (+) - terminal 7 C1
    • Left subwoofer speaker output (-) - terminal 3 C1
    • Right subwoofer speaker output (+) - terminal 6 C1
    • Right subwoofer speaker output (-) - terminal 2 C1
    ⇒If less than the specified value, test both circuits of the affected speaker for a short to ground.
  4. If all circuits test normal, reconnect all harness connectors at the amplifier.
  5. Radio ON, disconnect the appropriate speaker.
  6. Test for 5.0-7.5 volts between the signal circuit terminals and ground.
    7. ⇒If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the amplifier.
    ⇒If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
  7. If the circuit tests normal, replace the appropriate speaker.

Speaker Malfunction Amplifier Output Testing (+Y91)

  1. Ignition OFF, disconnect the C1 and C2 connectors at the amplifier.
  2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground:
    3. • Left front speaker output (+) - terminal 4 C2
    • Left front speaker output (-) - terminal 5 C2
    • Right front speaker output (+) - terminal 7 C2
    • Right front low speaker output (-) - terminal 6 C2
    • Left rear speaker output (+) - terminal 8 C2
    • Left rear speaker output (-) - terminal 7 C2
    • Right rear speaker output (+) - terminal 16 C2
    • Right rear speaker output (-) - terminal 8 C2
    • Front center speaker output (+) - terminal 13 C2
    • Front center speaker output (-) - terminal 12 C2
    • Left subwoofer speaker output (+) - terminal 1 C1
    • Left subwoofer speaker output (-) - terminal 2 C1
    • Right subwoofer speaker output (+) - terminal 7 C1
    • Right subwoofer speaker output (-) - terminal 3 C1
    ⇒If greater than the specified range, test both circuits of the affected speaker for a short to voltage.
  3. Radio OFF, test for infinite resistance between the appropriate signal circuit terminal listed below and ground:
    4. • Left front speaker output (+) - terminal 4 C2
    • Left front speaker output (-) - terminal 5 C2
    • Right front speaker output (+) - terminal 7 C2
    • Right front low speaker output (-) - terminal 6 C2
    • Left rear speaker output (+) - terminal 8 C2
    • Left rear speaker output (-) - terminal 7 C2
    • Right rear speaker output (+) - terminal 16 C2
    • Right rear speaker output (-) - terminal 8 C2
    • Front center speaker output (+) - terminal 13 C2
    • Front center speaker output (-) - terminal 12 C2
    • Left subwoofer speaker output (+) - terminal 1 C1
    • Left subwoofer speaker output (-) - terminal 2 C1
    • Right subwoofer speaker output (+) - terminal 7 C1
    • Right subwoofer speaker output (-) - terminal 3 C1
    ⇒If less than the specified value, test both circuits of the affected speaker for a short to ground.
  4. If all circuits test normal, reconnect all harness connectors at the amplifier.
  5. Radio ON, disconnect the appropriate speaker.
  6. Test for 5.0-7.5 volts between the signal circuit terminals and ground.
    7. ⇒If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the amplifier.
    ⇒If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
  7. If the circuit tests normal, replace the appropriate speaker.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Speaker Replacement Reference
    •  Control Module References for Amplifier and Radio replacement, setup, and programming