The vehicle has a shoulder belt height adjuster for the driver and right front passenger seating positions.
Adjust the height so the shoulder portion of the belt is on the shoulder and not falling off of it. The belt should be close to, but not contacting, the neck. Improper shoulder belt height adjustment could reduce the effectiveness of the safety belt in a crash. See How to Wear Safety Belts Properly.

To move it down, press the release button and move the height adjuster to the desired position.
After the adjuster is set to the desired position, try to move it down without pressing the release button to make sure it has locked into position.
Lap-Shoulder Belt
Safety Belt PretensionersOnStar Overview
If equipped, this vehicle has a comprehensive, in-vehicle system that can connect
to a live Advisor for Emergency, Security, Navigation, Connection, and Diagnostic
Services.
The OnStar system status light is next to the OnStar buttons. If the status light
is:
Solid Green: System is read ...
Starter Replacement (LUW)
Removal Procedure
Disconnect the negative battery cable. Refer to Battery Negative Cable
Disconnection and Connection.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
Remove the drivetrain and front suspension frame skid plate. Refer to
Drivet ...
Throttle Body Heater Inlet Hose Replacement (LUW)
Throttle Body Heater Inlet Hose Replacement
Callout
Component Name
Preliminary Procedure
Remove the air cleaner outlet duct. Refer to
Air Cleaner Outlet Duct Replacement.
Drain the cooling system. Refer to
Cooling ...