Circuit/System Testing
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2012 GMC Yukon XL, 2012 GMC Yukon, 2012 Chevrolet Tahoe, 2012 Chevrolet Suburban, and 2012 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition OFF, disconnect the harness connector at the ambient light sensor.
- Test for less than 5.0 Ω between the ground circuit listed below and ground.
- Ambient Light Sensor terminal C - CJ2
- Ambient Light Sensor terminal B - w/o CJ2
- If greater than the specified range, test the ground circuit for an open/high resistance.
- Ignition ON, verify the scan tool Ambient Light Sensor parameter is greater than 4.5 V.
- If less than the specified range, test the signal circuit for a short to ground. If the circuit tests normal, replace the BCM.
- Install a 3 A fused jumper wire between the signal circuit terminal listed below and the low reference circuit terminal listed below. Verify the scan tool Ambient Light Sensor parameter is less than 1.0 V.
- Ambient Light Sensor terminals A to B - w/o CJ2
- Ambient Light Sensor terminals D to C - CJ2
- 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.
- If all circuits test normal, test or replace the ambient light sensor.