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No Response From Amplifier

Possible Causes are:

NOTE: Ensure there is PCI Bus communication with other modules on the vehicle before proceeding. If not, refer to COMMUNICATIONS in DIAGNOSTIC TROUBLE CODE IDENTIFICATION  and SYMPTOM IDENTIFICATION  tables under RETRIEVING & CLEARING DIAGNOSTIC TROUBLE CODES under SELF-DIAGNOSTIC SYSTEM.
  1. Turn ignition on. The Radio must be turned on for the DRBIII(R) to get a response from the Amplifier. Using the DRBIII(R), attempt to communicate with the Radio. Was the DRBIII(R) able to I/D or communicate with the Radio? If yes, go to next step. If no, diagnose using appropriate procedure. See COMMUNICATION  under DIAGNOSTIC TESTS. Perform BODY VERIFICATION TEST VER 1  under VERIFICATION TESTS.
  2. Turn ignition off. Disconnect the Amplifier C1 harness connector. Using a 12-volt test light connected to 12 volts, probe both ground circuits. Is the test light illuminated for both circuits? If yes, go to next step. If no, repair the ground circuit for an open. Perform BODY VERIFICATION TEST VER 1  under VERIFICATION TESTS.
  3. Turn ignition off. Disconnect the Amplifier C1 harness connector. Using a 12-volt test light connected to ground, probe both Fused B (+) circuits. Is the test light illuminated for both circuits? If yes, go to next step. If no, repair the Fused B+ circuit for an open. Perform BODY VERIFICATION TEST VER 1  under VERIFICATION TESTS.
  4. Disconnect the Amplifier C1 harness connector. Use Scope Input Cable (CH7058), Cable To Probe Adapter (CH7062), and the Red and Black test probes. Connect the scope input cable to the channel one connector on the DRBIII(R). Attach the Red and Black leads and the cable to probe adapter to the scope input cable. Using the DRBIII(R), select Pep Module Tools. Select lab scope. Select Live Data. Select 12-volt square wave. Press F2 for Scope. Press F2 and use the down arrow to set voltage range to 20 volts. Set Probe to x10. Press F2 again, when complete. Connect the Black lead to the chassis ground. Connect the Red lead to the PCI Bus circuit in the Amplifier connector. Turn ignition on. Observe the voltage display on the DRBIII(R) Lab Scope. Does the voltage pulse from 0 to approximately 7.5 volts? If yes, replace the Amplifier. Perform BODY VERIFICATION TEST VER 1  under VERIFICATION TESTS. If no, repair the PCI Bus circuit for an open. Perform BODY VERIFICATION TEST VER 1  under VERIFICATION TESTS.
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