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Home › Chevrolet › 2009 › Uplander Base, 3.9 1 › Repair and Diagnosis › Suspension › Electronic Suspension › Automatic Level Control › Diagnostic Information and Procedures › Automatic Level Control Inflator Fill Valve Inoperative › Circuit/System Testing

Circuit/System Testing

  1. Ignition OFF, disconnect the air inflator air switch harness connector at the ALC sensor.
  2. Ignition ON, connect a 10A fused jumper wire between the ALC relay inflation timer relay coil control terminal 85 and the ground circuit terminal of the air inflator switch.
  3. Verify that a test lamp illuminates between the B+ circuit terminal A 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, test or replace the ALC compressor relay.
  4. Ignition OFF, disconnect the ALC solenoid valve harness connector at the ALC sensor.
  5. Verify that a test lamp illuminates between the ALC solenoid valve B+ circuit terminal B 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, test or replace the ALC solenoid valve.
  6. Verify that a test lamp illuminates between the ALC inflator solenoid valve B+ circuit terminal B and the ALC inflator solenoid valve ground terminal A.
    • If the test lamp illuminates, test or replace the ALC air inflator solenoid valve.
    • If the test lamp does not illuminate, test the ground circuit for open/high resistance.
  7. If all circuits test normal, test or replace the air inflator solenoid valve.
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