2004 Buick Lesabre Blown Ignition Fuses - Cranks but won't

INTERMITTENT CONDITIONS Intermittent Conditions Inspection or Test Action DEFINITION: Whether the symptom is a DTC or a customer complaint, the condition cannot be duplicated. Preliminary Perform the Diagnostic System Check-Engine Controls before starting. Refer to Diagnostic System Check - Engine Controls. Harness or Connector Many intermittent open or shorted circuits come and go with harness or connector movement caused by the following type conditions: Vibration à   Engine torque Bumps or rough pavement Test for intermittents by performing the applicable procedure from the following list: Move related connectors and wiring while monitoring the appropriate scan tool data. Move related connectors and wiring with the component commanded ON and OFF, with the scan tool-Observe the component operation. With the engine running, move related connectors and wiring while monitoring engine operation. Verify whether the harness or connector movement affects any of the following systems: Data displayed à   Component or system operation Engine operation Repair the components as necessary. Refer to Electrical Connections or Wiring in this table. Electrical Connections or Wiring Intermittents are usually caused by one or more of the following conditions: Poor electrical connections Terminal tension Wiring problems Carefully inspect the suspected circuit for the following conditions: You may need to trace the wires to the fuse. Check connections at PCM.

Poor mating of the connector halves Terminals backed out or not fully seated in the connector body Improperly formed or damaged terminals-Test for poor terminal tension. Poor terminal to wire connections including terminals crimped over insulation-This requires removing the terminal from the connector body. Corrosion or water intrusion- Pierced or damaged insulation can allow moisture to enter the wiring. The conductor can corrode inside the insulation, with little visible evidence. Look for swollen and stiff sections of wire in the suspect circuits. Wires that are broken inside the insulation Pinched, cut or rubbed through wiring in the harness Wiring that is in contact with hot exhaust components Repair condition as necessary. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Control Module Power and Grounds Component Power and Grounds Poor power or ground connections can cause widely varying symptoms. Test all control module power circuits. Many vehicles have multiple circuits supplying power to the control module. Other components in the system may have separate power circuits that may also need to be tested. Inspect connections at the module or component connectors, fuses, and any intermediate connections between the power source and the module or component. A test lamp or a DMM may indicate that voltage is present, but neither tests the ability of a circuit to carry sufficient current. Ensure that the circuit can carry the current necessary to operate the component. Refer to Power Distribution Schematics in Wiring Systems. Test all control module ground and system ground circuits. The control module may have multiple ground circuits. Other components in the system may have separate grounds that may also need to be tested. Inspect grounds for clean and tight connections at the grounding point. Inspect the connections at the component and in splice packs, where applicable. Ensure that the circuit can carry the current necessary to operate the component. Refer to Ground Distribution Schematics in Wiring Systems. Temperature Sensitivity An intermittent condition may occur when a component or connection reaches normal operating temperature. The condition may occur only when the component or connection is cold, or only when the connection is hot.

Look at pwoer and ground to PCM and connector for the Ignition switch. You may need to trace the wires from the fuse block with the fuse that blows, wheather its inside the car or under the hood.