Circuit/System Testing

2008 Chevrolet Chevy Express G2500, Van Cargo, 6.6 6SECTION Circuit/System Testing
WARNING: This page is about a different car, the 2008 Chevrolet Malibu Classic. However, it is still accessible from the selected car via links, so may be relevant.
  1. Ignition OFF, disconnect the harness connector at the ambient light sensor.
  2. Ignition OFF, test for less than 5 ohms of resistance between the appropriate low reference circuit listed below and ground.
    • Terminal B (with C60)
    • Terminal C (with C68)
    • If greater than the specified range, test the low reference circuit for an open/high resistance.
  3. Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.65 volts.
    • If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.
  4. Install a 3A fused jumper wire between the appropriate signal circuit and the low reference listed below. Verify the scan tool Ambient Light Sensor parameter is less than 0.196 volts.
    • Terminal A and terminal B (with C60)
    • Terminal D and terminal C (with C68)
    • 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 BCM.
  5. If all circuits test normal, test or replace the ambient light sensor.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • β€’ You smell fuel, burning insulation, or see smoke.
  • β€’ Brakes feel soft, pull hard to one side, or make grinding noises.
  • β€’ The engine overheats, stalls repeatedly, or misfires under load.
  • β€’ You are missing required tools, torque specs, or safe lifting equipment.
  • β€’ You are not confident in the next step or safety outcome.