Bus +/- Signals Open Or No Response From Instrument Cluster

Possible Causes:

Open Ground Circuit
Open Fused Ignition Switch Output Circuit
Open Fused B+ Circuit
Open PCI Bus Circuit
Instrument Cluster

Testing

Turn the ignition off. Turn all lights off. Disconnect the Instrument Cluster harness connector. Using a 12-volt test light connected to 12-volts, probe the ground circuit. Is the test light illuminated? If yes, go to next step. If no, repair the ground circuit for an open. Perform BODY VERIFICATION TEST .
Turn the ignition off. Disconnect Instrument Cluster harness connector. Turn the 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. Perform BODY VERIFICATION TEST .
Turn the ignition off. Disconnect the Instrument Cluster 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. Perform BODY VERIFICATION TEST .
Disconnect the Instrument Cluster 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. With 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 she Red lead to the PCI Bus circuit in the Instrument Cluster connector. Turn the 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 .
If there are no possible causes remaining replace the Instrument Cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION in ANALOG INSTRUMENT PANELS - LIBERTY article. Perform BODY VERIFICATION TEST .