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Home >> Isuzu >> 2007 >> Ascender RWD >> Repair and Diagnosis >> External Pages >> Different car >> Section 500 (Cruise Control System) >> Diagnostic Information and Procedures >> Cruise Control Malfunction >> Circuit/System Testing

Circuit/System Testing

WARNING: This page is about a different car, the 2009 GMC Envoy and 2009 Chevrolet TrailBlazer. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the X4 harness connector at the turn signal/multifunction switch.
  2. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal A and ground.
    • If the test lamp does not illuminate, test the circuit for a short to ground or an open/high resistance.
  3. Verify the Cruise Control ON/OFF Switch parameter displays Off.
    • If not the specified value, test the signal circuit terminal B for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Install a 3A fused jumper wire between the signal circuit terminal B and the B+ circuit terminal A. Verify the Cruise Control ON/OFF Switch parameter displays On.
    • If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  5. Verify that the scan tool Cruise Set/Coast Switch parameter displays Inactive.
    • If not the specified value, test the signal circuit terminal C for a short to voltage. If the circuit tests normal, replace the ECM.
  6. Install a 3A fused jumper wire between the signal circuit terminal C and the B+ circuit terminal A. Verify the scan tool Cruise Set/Coast Switch parameter displays Active.
    • If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  7. Verify that the scan tool Cruise Resume/Accel. Switch parameter displays Inactive.
    • If not the specified value, test the signal circuit terminal D for a short to voltage. If the circuit tests normal, replace the ECM.
  8. Install a 3A fused jumper wire between the signal circuit terminal D and the B+ circuit terminal A. Verify the scan tool Cruise Resume/Accel. Switch parameter displays Active.
    • If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  9. If all circuits test normal, test or replace the turn signal/multifunction switch.
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