Buick 2011 Lucerne Owner's Manual page 166

It controls the following systems:
Headlamps
Taillamps
Parking Lamps
License Plate Lamps
Instrument Panel Lights
Fog Lamps
4-10
The exterior lamps control
is located on the
instrument panel to the
left of the steering wheel.
The exterior lamps control has four positions:
Turn the control to this position to turn off the
exterior lamps.
Turn the control to this position to
automatically turn on the headlamps at normal
brightness, together with the following:
Parking Lamps
Instrument Panel Lights
Turn the control to this position to
turn on the parking lamps together with the following:
Taillamps
License Plate Lamps
Instrument Panel Lights
Turn the control to this position to turn
on the headlamps together with the following lamps
listed below. A warning chime sounds if the driver's door
is opened while the ignition switch is off and the
headlamps are on.
Parking Lamps
License Plate Lamps
Instrument Panel Lights
Push the exterior lamps control in to
turn on the fog lamps.
See Fog Lamps on page 4 12.