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Circuit/System Testing

WARNING: This page is about a different car, the 2009 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the appropriate air temperature sensor.
  2. Ignition OFF, test for less than 10 ohms between the following low reference circuit terminal and ground.
    • Inside air temperature sensor terminal 2.
    • Ambient temperature sensor terminal B.
    • If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, verify the appropriate scan tool Air Temp Sensor parameter is less than -35°C (-39°F).
    • If greater than the specified range, test the following signal circuit terminal for a short to ground. If the circuit tests normal, replace the HVAC control module.
      • Inside air temperature sensor terminal 1.
      • Ambient temperature sensor terminal A.
  4. Install a 3A fused jumper wire between the following signal circuit terminal and the low reference circuit terminal. Verify the scan tool Air Temp Sensor parameter is greater than 85°C (185°F).
    • Inside air temperature sensor terminal 1 and 2.
    • Ambient temperature sensor terminal A and B.
    • If less than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  5. If all circuits test normal, test or replace the air temperature sensor.
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