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Circuit/System Testing

WARNING: This page is about a different car, the 2008 Buick LaCrosse and 2008 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the blower motor control processor.
  2. Test for less than 1.0 ohm of resistance between the ground circuit terminal A and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal C and ground.
    • If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, replace the blower motor control processor.
  4. Ignition OFF, connect the harness connector at the blower motor control processor and disconnect the harness connector at the blower motor.
  5. Connect a test lamp between the control circuit terminal B and B+.
  6. Ignition ON, command the blower motor ON and OFF with a scan tool, the test lamp should turn ON and OFF when changing between the commanded states.
    • If the test lamp is always OFF, test the ground circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the blower motor control processor.
    • If the test lamp is always ON, test the ground circuit for a short to ground. If the circuit tests normal, replace the blower motor control processor.
  7. Connect a test lamp between the control circuit terminal A and ground.
  8. Turn the blower motor ON and cycle between low and high speeds. The test lamp should illuminate and change in intensity as the blower speed is varied.
    • If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the blower motor control processor.
    • If the test lamp does not change intensity, test the control circuit for a short to voltage. If the circuit tests normal, replace the blower motor control processor.
  9. If all circuits test normal, test or replace the blower motor.
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