GMC 2007 Sierra - Manual (Page 222)

The headlamp control has four positions:
9 (Off): Turn the control to this position to turn
off the Daytime Running Lamps (DRL) and
the automatic headlamps.
AUTO (Automatic): Turn the control to this
position to activate the automatic headlamp mode.
; (Parking Lamps): Turn the control to this
position to turn on the parking lamps, together with
the following:
• Sidemarker Lamps
• Taillamps
• License Plate Lamps
• Instrument Panel Lights
• Roof Marker Lamps (If the vehicle has them)
5 (Headlamps): Turn the control to this position
to turn on the headlamps, together with the
previously listed lamps and lights.
Switch the headlamps from high to low-beam by
pushing the turn signal/high-beam lever towards
the instrument panel.
A circuit breaker protects the headlamps. If you
have an electrical overload, the headlamps
will flicker on and off. Have your headlamp wiring
checked right away if this happens.
Headlamps on Reminder
A reminder chime will sound when the headlamps
or parking lamps are manually turned on and
your ignition is off and a door is open. To disable
the chime, turn the light off.
Daytime Running Lamps (DRL)
Daytime Running Lamps (DRL) can make it easier
for others to see the front of your vehicle during
the day. DRL can be helpful in many different
driving conditions, but they can be especially
helpful in the short periods after dawn and before
sunset. Fully functional DRL are required on all
vehicles first sold in Canada.
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