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HOMESERVICE MANUALSCHEVROLET2008CHEVY EXPRESS G2500, VAN CARGO, 6.6 6REPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 2061 (CELLULAR SYSTEMS, ENTERTAINMENT SYSTEMS & NAVIGATION SYSTEMS)DIAGNOSTIC INFORMATION AND PROCEDURESSPEAKER MALFUNCTIONCIRCUIT/SYSTEM TESTING
2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6

Circuit/System Testing

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2010 GMC Sierra, 2010 GMC Cab & Chassis Sierra, 2010 Chevrolet Silverado, and 2010 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

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.
    • 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.
    • 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 X1 harness connector at the audio amplifier.
  2. Ignition OFF, test for less than 10 ohms between the ground circuit terminal 8 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, test for B+ between the B+ circuit terminal 4 and ground.
    • If less then specified value, test the circuit for a short to ground, or an open/high resistance.
  4. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
  5. For vehicles without RPO code Y91 only: Radio ON, test for B+ between the signal circuit terminal 8 and ground.
    • 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. If all circuits test normal, replace the audio amplifier.

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

  1. Ignition OFF, disconnect the X3 connector at the audio amplifier.
  2. Ignition ON, radio ON, test for B+ between the signal circuit terminal 8 and ground.
    • 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 ON, radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground:
    • 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.
  4. If all circuits test normal, replace the audio amplifier.

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

  1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
  2. Ignition ON, radio ON, test for B+ between the signal circuit terminal 8 and ground.
    • 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. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground:
    • 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.
  4. Ignition OFF, reconnect the X3 harness connector at the audio amplifier.
  5. Disconnect the X2 harness connector at the rear seat audio (RSA) module.
  6. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground:
    • 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.
  7. Ignition OFF, reconnect the X2 harness connector at the rear seat audio (RSA) module.
  8. Disconnect the X3 harness connector at the audio amplifier.
  9. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground:
    • 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.
  10. If all circuits test normal, replace the audio amplifier.

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

  1. Ignition OFF, disconnect the X2 and X3 harness connectors at the audio amplifier.
  2. Ignition ON, radio ON, test for B+ between the signal circuit terminal 8 and ground.
    • 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. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground:
    • Left front low level audio signal (+) - terminal 11 X3
    • Left front low level audio signal (-) - terminal 12 X3
    • Right front low level audio signal (+) - terminal 3 X3
    • Right front low level audio signal (-) - terminal 4 X3
    • Left rear low level audio signal (+) - terminal 15 X2
    • Left rear low level audio signal (-) - terminal 14 X2
    • Right rear low level audio signal (+) - terminal 16 X2
    • Right rear low level audio signal (-) - terminal 8 X2
    • 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 audio amplifier.

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

  1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
  2. Ignition ON, radio ON, test for B+ between the signal circuit terminal 8 and ground.
    • 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. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground:
    • 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.
  4. Ignition OFF, reconnect the X3 harness connector at the audio amplifier.
  5. Disconnect the X2 harness connector at the rear seat audio (RSA) module.
  6. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground:
    • 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.
  7. Ignition OFF, reconnect the X2 harness connector at the rear seat audio (RSA) module.
  8. Disconnect the X2 harness connector at the audio amplifier.
  9. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below and ground:
    • Left rear low level audio signal (+) - terminal 15 X2
    • Left rear low level audio signal (-) - terminal 14 X2
    • Right rear low level audio signal (+) - terminal 16 X2
    • Right rear low level audio signal (-) - terminal 8 X2
    • 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.
  10. If all circuits test normal, replace the audio amplifier.

Speaker Malfunction Amplifier Output Testing (-Y91)

  1. Ignition OFF, disconnect the X1 and X2 connectors at the audio amplifier.
  2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground:
    • Left front speaker output (+) - terminal 4 X2
    • Left front speaker output (-) - terminal 3 X2
    • Right front speaker output (+) - terminal 2 X2
    • Right front low speaker output (-) - terminal 1 X2
    • Left rear speaker output (+) - terminal 8 X2
    • Left rear speaker output (-) - terminal 7 X2
    • Right rear speaker output (+) - terminal 6 X2
    • Right rear speaker output (-) - terminal 5 X2
    • Left subwoofer speaker output (+) - terminal 7 X1
    • Left subwoofer speaker output (-) - terminal 3 X1
    • Right subwoofer speaker output (+) - terminal 6 X1
    • Right subwoofer speaker output (-) - terminal 2 X1
    • 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:
    • Left front speaker output (+) - terminal 4 X2
    • Left front speaker output (-) - terminal 3 X2
    • Right front speaker output (+) - terminal 2 X2
    • Right front low speaker output (-) - terminal 1 X2
    • Left rear speaker output (+) - terminal 8 X2
    • Left rear speaker output (-) - terminal 7 X2
    • Right rear speaker output (+) - terminal 6 X2
    • Right rear speaker output (-) - terminal 5 X2
    • Left subwoofer speaker output (+) - terminal 7 X1
    • Left subwoofer speaker output (-) - terminal 3 X1
    • Right subwoofer speaker output (+) - terminal 6 X1
    • Right subwoofer speaker output (-) - terminal 2 X1
    • 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 audio amplifier.
  5. Radio ON, disconnect the appropriate speaker.
  6. Test for 5.0-7.5 volts between the signal circuit terminals and ground.
    • If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the audio amplifier.
    • If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the audio amplifier.
  7. If the circuit tests normal, replace the appropriate speaker.

Speaker Malfunction Amplifier Output Testing (+Y91)

  1. Ignition OFF, disconnect the X1 and X2 connectors at the audio amplifier.
  2. Radio ON, test for less than 1 volt between the appropriate signal circuit terminal listed below and ground:
    • Left front speaker output (+) - terminal 4 X2
    • Left front speaker output (-) - terminal 5 X2
    • Right front speaker output (+) - terminal 7 X2
    • Right front low speaker output (-) - terminal 6 X2
    • Left rear speaker output (+) - terminal 8 X2
    • Left rear speaker output (-) - terminal 7 X2
    • Right rear speaker output (+) - terminal 16 X2
    • Right rear speaker output (-) - terminal 8 X2
    • Front center speaker output (+) - terminal 13 X2
    • Front center speaker output (-) - terminal 12 X2
    • Left subwoofer speaker output (+) - terminal 1 X1
    • Left subwoofer speaker output (-) - terminal 2 X1
    • Right subwoofer speaker output (+) - terminal 7 X1
    • Right subwoofer speaker output (-) - terminal 3 X1
    • 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:
    • Left front speaker output (+) - terminal 4 X2
    • Left front speaker output (-) - terminal 5 X2
    • Right front speaker output (+) - terminal 7 X2
    • Right front low speaker output (-) - terminal 6 X2
    • Left rear speaker output (+) - terminal 8 X2
    • Left rear speaker output (-) - terminal 7 X2
    • Right rear speaker output (+) - terminal 16 X2
    • Right rear speaker output (-) - terminal 8 X2
    • Front center speaker output (+) - terminal 13 X2
    • Front center speaker output (-) - terminal 12 X2
    • Left subwoofer speaker output (+) - terminal 1 X1
    • Left subwoofer speaker output (-) - terminal 2 X1
    • Right subwoofer speaker output (+) - terminal 7 X1
    • Right subwoofer speaker output (-) - terminal 3 X1
    • 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 audio amplifier.
  5. Radio ON, disconnect the appropriate speaker.
  6. Test for 5.0-7.5 volts between the signal circuit terminals and ground.
    • If less then the specified range test the circuit for an open/high resistance. If the circuit tests normal, replace the audio amplifier.
    • If greater then the specified range test the circuit for a short to voltage. If the circuit tests normal, replace the audio amplifier.
  7. If the circuit tests normal, replace the appropriate speaker.
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