2005 GMC ENVOY night vision

There is a delay in the transition between the daytime
and nighttime operation of the Daytime Running
Lamps (DRL) and the automatic headlamp systems, so
that driving under bridges or bright overhead street
lights does not affect the system. The DRL and
automatic headlamp system will only be affected when
the light sensor sees a change in lighting lasting
longer than the delay.
If you start your vehicle in a dark garage, the automatic
headlamp system will come on immediately. Once
you leave the garage, it will take about one minute for
the automatic headlamp system to change to DRL if it is
light outside. During that delay, your instrument panel
cluster may not be as bright as usual. Make sure
your instrument panel brightness control is in the full
bright position.
To idle your vehicle with the automatic headlamp system
off, set the parking brake while the ignition is off. Then
start your vehicle. The automatic headlamp system will
stay off until you release the parking brake, shift out of
park or turn the exterior lamp control to the off position as
described in “Exterior Lamps” listed previously.Fog Lamps
Your vehicle may have this feature. Use your fog lamps
for better vision in foggy or misty conditions. Your
ignition must be in RUN for your fog lamps to work.
The fog lamp button is
located on the instrument
panel to the right of
the exterior lamps knob.
Press the button to turn the fog lamps on. Press the
button again to turn them off. A light will glow near the
button while the fog lamps are on. Fog lamps will
turn off whenever your high-beam headlamps are on.
3-17

Driving at Night
Night driving is more dangerous than day driving. One
reason is that some drivers are likely to be impaired — by
alcohol or drugs, with night vision problems, or by fatigue.Here are some tips on night driving.
Drive defensively.
Do not drink and drive.
Since you cannot see as well, you may need to
slow down and keep more space between you
and other vehicles.
Slow down, especially on higher speed roads. Your
headlamps can light up only so much road ahead.
In remote areas, watch for animals.
If you are tired, pull off the road in a safe place
and rest.
No one can see as well at night as in the daytime. But
as we get older these differences increase. A
50-year-old driver may require at least twice as much
light to see the same thing at night as a 20-year-old.
4-30

What you do in the daytime can also affect your night
vision. For example, if you spend the day in bright
sunshine you are wise to wear sunglasses. Your eyes
will have less trouble adjusting to night. But if you
are driving, do not wear sunglasses at night. They may
cut down on glare from headlamps, but they also
make a lot of things invisible.
You can be temporarily blinded by approaching
headlamps. It can take a second or two, or even several
seconds, for your eyes to re-adjust to the dark. When
you are faced with severe glare, as from a driver
who does not lower the high beams, or a vehicle with
misaimed headlamps, slow down a little. Avoid
staring directly into the approaching headlamps.
Keep your windshield and all the glass on your vehicle
clean — inside and out. Glare at night is made much
worse by dirt on the glass. Even the inside of the glass
can build up a lm caused by dust. Dirty glass makes
lights dazzle and ash more than clean glass would,
making the pupils of your eyes contract repeatedly.
Remember that your headlamps light up far less of a
roadway when you are in a turn or curve. Keep
your eyes moving; that way, it is easier to pick out dimly
lighted objects. Just as your headlamps should be
checked regularly for proper aim, so should your eyes
be examined regularly. Some drivers suffer from
night blindness — the inability to see in dim light — and
are not even aware of it.Driving in Rain and on Wet Roads
Rain and wet roads can mean driving trouble. On a wet
road, you cannot stop, accelerate, or turn as well
because your tire-to-road traction is not as good as on
dry roads. And, if your tires do not have much tread
left, you will get even less traction. It is always wise to
go slower and be cautious if rain starts to fall while
you are driving. The surface may get wet suddenly when
your reexes are tuned for driving on dry pavement.
4-31