Circuit/System Verification
WARNING: This page does not describe the selected car, but rather 8 other vehicles, including the 2008 GMC Yukon XL, 2008 GMC Yukon, 2008 Chevrolet Tahoe, 2008 Chevrolet Suburban, and 2008 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
- Ignition ON, observe the scan tool Headlamp Switch parameter while turning the headlamp switch ON and OFF. The reading should toggle between ACTIVE and INACTIVE.
- If the reading does not change between the commanded states, refer to Headlamp Switch Malfunction .
- Observe the scan tool Flash to Pass Switch parameter while applying and releasing the flash to pass switch. The reading should toggle between ACTIVE and INACTIVE.
- If the reading does not change between the commanded states, refer to Turn Signal/Multifunction Switch Malfunction .
- Observe the scan tool High Beam Select Switch parameter while applying and releasing the high beam select switch. The reading should toggle between ACTIVE and INACTIVE.
- If the reading does not change between the commanded states, refer to Turn Signal/Multifunction Switch Malfunction .
- Command the Low Beams ON and OFF with a scan tool. The Low Beam Relay Command should turn ON and OFF when commanded.
- If the reading does not change between the commanded states, refer to Headlamps Malfunction - Low Beam .
- Command the High Beams ON and OFF with a scan tool. The High Beam Relay Command should turn ON and OFF when commanded.
- If the reading does not change between the commanded states, refer to Headlamps Malfunction - High Beam .
- Command the High Beams ON and OFF with a scan tool. The High Beam Indicators should turn ON and OFF.
- If the High Beam Indicators do not turn ON and OFF, refer to High Beam Indicators Malfunction .