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Circuit System Testing

WARNING: This page is about a different car, the 2007 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the HVAC harness connector at the a/c switch.
  2. Test for less than 1.0 ohm of resistance between the HVAC control module ground circuit terminal C1 pin 12 and ground.
    • If greater than the specified range, test the ground circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool ECM A/C request parameter is No or open.
    • If not the specified value, test the a/c request signal circuit terminal HVAC control module terminal C1 pin 8 for a short to ground. If the circuit tests normal, replace the HVAC Control Module.
  4. Install a 3A fused jumper wire between the signal circuit terminal C1 pin 8 and the ground circuit terminal C1 pin 12. Verify the scan tool ECM a/c request switch parameter is YES or closed.
    • If not the specified value, test the a/c request signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
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