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 Stop Lamp Relay Command parameter while pressing and releasing the brake pedal. The reading should change between ON and OFF..
- If not the specified value, refer to the Stop Lamp Switch Malfunction .
- Ignition ON, observe the left, right and center high mount stop lamps while pressing and releasing the brake pedal. The stop lamps should turn ON and OFF.
- If the left and or right stop lamps are always ON or OFF, refer to the Stop Lamp Malfunction .
- If the center high mount stop lamp is always ON or OFF, refer to the High Mount Stop Lamp Replacement (Escalade) or High Mount Stop Lamp Replacement (Yukon) or High Mount Stop Lamp Replacement (Avalanche) or High Mount Stop Lamp Replacement (GMC Yukon Two-mode Hybrid) Malfunction.