GM Chevrolet Avalanche - Manual (Page 172)

Your vehicle has a light sensor located on the top of the
instrument panel. Be sure it is not covered, or the
system will be on whenever the ignition is 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 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 approximately
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. See Instrument Panel
Brightness on page 3-17.
Fog Lamps
If your vehicle has fog lamps you can use them for
better vision in foggy or misty conditions. Your parking
lamps and/or low-beam headlamps must be on for
your fog lamps to work.
The fog lamp button is
located on the left side of
your instrument panel.
Press the button to turn the fog lamps on while the
headlamps or parking lamps are on. Press the button
again to turn them off. An indicator light will glow
near the button when the fog lamps are on.
Remember, fog lamps alone will not give off as much
light as your headlamps. Never use your fog lamps
in the dark without turning on the headlamps.
The fog lamps will go off whenever your high-beam
headlamps come on. When the high beams go off, the
fog lamps will come on again.
The fog lamps will be cancelled after the ignition is
turned off. If you still want to use the fog lamps after you
restart the vehicle, you will need to press the fog
lamp button again.
3-16