BUS +/- Signals Open Or No Response From Automatic Zone Control Module

Possible Causes are:

ATTEMPT TO COMMUNICATE WITH THE BCM
FUSED B (+) CIRCUIT OPEN
FUSED IGNITION SWITCH OUTPUT CIRCUIT OPEN
OPEN PCI BUS CIRCUIT
AUTOMATIC ZONE CONTROL MODULE

Turn ignition on. Using the DRBIII(R), enter Body then Body Computer. Was the DRBIII(R) able to I/D or communicate with the BCM? 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.
Turn ignition off. Disconnect the Automatic Zone Control Module C2 harness connector. Using a 12-volt test light connected to ground, probe the Fused B+ circuit. Is the test light illuminated? If yes, go to next step. If no, repair the Fused B+ circuit for an open or short. See WIRING DIAGRAMS . Perform BODY VERIFICATION TEST VER 1 under VERIFICATION TESTS.
Turn ignition off. Disconnect the Automatic Zone Control Module C2 harness connector. Turn ignition on. Using a 12-volt test light connected to ground, probe the Fused Ignition Switch Output circuit. Is the test light illuminated? If yes, go to next step. If no, repair the Fused Ignition Switch Output circuit for an open or short. See WIRING DIAGRAMS . Perform BODY VERIFICATION TEST VER 1 under VERIFICATION TESTS.

NOTE: Ensure there is PCI Bus communication with other modules on the vehicle before proceeding. If no, diagnose using appropriate procedure. See COMMUNICATION under DIAGNOSTIC TESTS.

Disconnect the Automatic Zone Control Module C2 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 the 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 AZC 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, go to next step. If no, repair the PCI Bus circuit for an open. Perform BODY VERIFICATION TEST VER 1 under VERIFICATION TESTS.
If there are no possible causes remaining, replace the Automatic Zone Control Module. Perform BODY VERIFICATION TEST VER 1 under VERIFICATION TESTS.