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Circuit/System Testing

WARNING: This page is about a different car, the 2007 Cadillac XLR. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the sunload sensor assembly.
  2. Ignition OFF, test for less than 1 ohm of resistance between the low reference circuit terminal C and ground.
    • 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 scan tool ambient light sensor parameter is greater than 250 counts.
    • If less than the specified range, test the signal circuit terminal D 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 D and the low reference circuit terminal C. Verify the scan tool ambient light sensor parameter is less than 5 counts.
    • If greater 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, replace the sun load sensor assembly.
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