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Circuit/System Testing

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IMPORTANT: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
  1. Inspect the Ign Switch fuse for open. The fuse should be OK.
    • If the fuse is open, test the following circuits for a short to ground, if all circuits test OK, replace the BCM.
      • Battery positive voltage of the ignition switch
      • Accessory voltage
      • Off/Run crank voltage
      • Ignition 1 voltage
  2. Disconnect the ignition switch connector.
  3. Test for battery positive voltage between the battery positive voltage circuit of the ignition switch and ground.
    • If less than battery positive voltage, repair the circuit for an open/high resistance
    4. IMPORTANT: The ignition switch component test must be preformed before proceeding with this test to verify the integrity of the switch.
  4. Perform the ignition switch component test.
    • If the ignition switch fails, replace the ignition switch.
  5. Ignition OFF, disconnect BCM connector C1, test for less than 1.0 volt between the following circuits of the BCM and ground.
  6. Ignition key out, test for less than 1.0 volt between the following circuits of the BCM and ground.
    • Ignition key resistor signal
    • Off/Run crank
    • Accessory voltage
    • Ignition 1 voltage
    • If more than 1.0 volt, repair the circuit for a short to voltage.
  7. Test for less than 1.0 ohm of resistance between the BCM and the ignition switch on the following circuits.
    • Ignition key resistor signal
    • Off/Run crank
    • Accessory voltage
    • Ignition 1 voltage
    • If greater than 5 ohms, repair the circuit for open/high resistance
  8. Test for infinite resistance between the ignition key resistor signal circuit of the BCM and ground.
    • If less than infinite resistance, repair the signal circuit for a short to ground.
  9. Replace the BCM.
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