Diagnostic Procedure
*NO RESPONSE FROM AUTOMATIC TEMPERATURE CONTROL MODULE - DIAGNOSTIC PROCEDURE
| TEST | ACTION | APPLICABILITY |
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| 1 | Turn the ignition on. With the DRBIII®, enter Body then Body Computer. Was the DRBIII® able to I/D or communicate with the BCM?
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| 2 | Turn the ignition off. Disconnect the ATC C1 harness connector. Using a 12-volt test light connected to 12-volts, probe the Ground circuit. Is the test light illuminated?
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All |
| 3 | Turn the ignition off. Disconnect the ATC C1 harness connector. Using a 12-volt test light connected to ground, probe the Fused B+ circuit. Is the test light illuminated?
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| 4 | Turn the ignition off. Disconnect the ATC C1 harness connector. Turn the ignition on. Using a 12-volt test light connected to ground, probe the Fused Run Relay Output circuit. Is the test light illuminated?
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| 5 |
NOTE:
Ensure there is PCI Bus communication with other modules on the vehicle before proceeding. If not, refer to the SYMPTOM LIST from the menu and repair as necessary. Disconnect the ATC 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 DRB. Attach the red and black leads and the cable to probe adapter to the scope input cable.With the DRBIII® 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. Press F2 again when complete.Connect the Black lead to the chassis ground. Connect the Red lead to the PCI Bus circuit in the ATC connector.Turn the ignition on.Observe the voltage display on the DRBIII® Lab Scope.Does the voltage pulse from 0 to approximately 7.5 volts?
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| 6 | If there are no possible causes remaining, view repair.
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