GMC 2003 Sierra - Manual (Page 169)

Automatic Heacîlamp System
Whan it is dark enough outside, your automalic
headlamp system will turn on your headlamps aî the
norma! brightness along with olher lamps such as
the laillamps, sidemarlier, parking lamps and |he
instrurinenl panel lights. The radio lights will also be dim.
Your vehicle is equipped with a light sensor localed
on the top ol The fnstrumen! panel in the defroster gnile.
Be sure il is no1 covered, or the system' wifi be on
whenever the ignibon J3 on.
The system may also turn on your headlamps when
driving through a parking garage^ heavy overcast
weather or a tunnel. This is normal.
There is a delay in the transition between the daylime
and nighttime operation of the Daytime Running
Lanrrps fDRL) and the aulomatic headlamp systems so
that driving urrder bridges or bright overhead street
lights does nol affect Ihe system, The DRL and
fluiomalic headlamp system will only be aHecled when
the tight sansor sees a change in lighting lasting
longer than the delay.
Jf you start your vehicle in a dark garagen the autocratic
headlamp system will come on immediately. Once
you leave the garage, il will take approximately
one minule tor Ihe automatic headlamp syslem to
change lo DRL it II is bright enough outside. During thai
delay, your in struma nt panel cluster may not bg as
brlgfil as usual. Make sure your mstrumeni panel
bipghtness control is in the fulf bright position. See
"Instrument Panel Brightness Conlnol" under inisrtor
iBiTips on page 3- i 7.
To idle your vehicle with the automatic headlamp
system oft, turn ihe control lo ihe off posilion.
You may be аЫе to turn q H your autcmatLc headlamp
system See Dayiime Running Lamps (DRL) later In this
section lor more information.
You may be able To Turn off your Automalic Headiamp
Syslem. Sea '‘Daybme Running Lamps ^DRL)" later
in this section for more information,
As with any vehicle, you should turn on The regular
headlamp system when you need them.
Lamps On Reminder
A reminder chime will sound when your headlamps or
parking lamps are manually turned on and your ignition is
oK. In LOCK, ACCESSORY, or your boor Is open. To
disable the chime, turn thg light off then back an.
Daytime Running Lamps
Daytime Running Lamps (DRL) can make Л easier for
others to sen
The front af your vehicle during the
day. DRL can be helpful in many tJIfferenl driving
conditions,, bdl they c^n be especially
helpful rn the short
periods after dawn and belore sunael Fully function aS
daytime running
lamps зге required on all vehicles
first sold in Canada.
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