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Home >> Cadillac >> 2007 >> CTS Base, 2.8 T, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 220 (Cellular System, Entertainment System, And Navigation System) >> Diagnostic Information and Procedures >> Speakers Inoperative - All >> Circuit/System Testing
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Circuit/System Testing

WARNING: This page is about a different car, the 2007 Cadillac STS. However, it is still accessible from the selected car via links, so may be relevant.
IMPORTANT: Diagnose any communication DTCs before performing this diagnostic.
  1. Disconnect the harness connector at the amplifier that contains the suspect inoperative channel. Connect a DMM between the suspect low level audio signal circuits and operate the radio.
    • If AC voltage is not present on all inputs, replace the radio.
  2. At the amplifier harness connector, test for less than 1 ohm of resistance between the ground circuit terminal and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Verify that a test lamp illuminates between the B+ circuit terminal and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
    • If all circuits test normal, replace the amplifier.
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