When it is dark enough outside and the exterior lamp control is in the automatic position, the headlamps come on automatically.

The vehicle has a light sensor on top of the instrument panel. Make sure it is not covered, or the headlamps will be on when they are not needed.
The system may also turn on the headlamps when driving through a parking garage or tunnel.
Lights On with Wipers
If the windshield wipers are activated in daylight with the engine on, and the exterior lamp control is in AUTO, the headlamps, parking lamps, and other exterior lamps come on. The transition time for the lamps coming on varies based on wiper speed. When the wipers are not operating, these lamps turn off.
Move the exterior lamp control to
or
to disable this feature.
Daytime Running Lamps (DRL)
Hazard Warning FlashersService Publications Ordering Information
Service Manuals
Service Manuals have the diagnosis and repair information on the engines, transmission,
axle, suspension, brakes, electrical, steering, body, etc.
Service Bulletins
Service Bulletins give additional technical service information needed to knowledgeably
service General Motors c ...
Moveable Window Schematics
Defogger Schematics
Window System Component Views
Window Systems Component Views
...
Installation Procedure
Clean and prepare the attaching surfaces for welding.
Apply structural adhesive to the attaching flanges.
Position the body side outer lower panel on the vehicle
Verify the fit of the body side outer lower panel.
Clamp the body side outer lower panel into position.
Spot ...