Headlamp High/Low-Beam Changer; Flash-To-Pass - Chevrolet 2008 TrailBlazer Owner's Manual

If you have a trailer towing option with added wiring
for the trailer lamps, a turn signal flasher is used.
With this flasher installed, the signal indicator flashes
even if a turn signal bulb is burned out. Check the front
and rear turn signal lamps regularly to make sure they
are working.
Turn Signal On Chime
A chime sounds if the turn signal has been on 3/4 of a
mile (1.2 km). Move the turn signal lever to off.

Headlamp High/Low-Beam Changer

To change the headlamps from low to high beam,
push the lever toward the instrument panel. To return to
low-beam headlamps, pull the multifunction lever
toward you. Then release it.
3-8
When the high beams are
on, this indicator light on
the instrument panel
cluster will also be on.

Flash-to-Pass

This feature lets you use your high-beam headlamps to
signal a driver in front of you that you want to pass.
It works even if your headlamps are in the automatic
position.
To use it, pull the turn signal lever toward you, then
release it.
If the headlamps are in the automatic position or on
low beam, the high-beam headlamps turn on.
They will stay on as long as you hold the lever toward
you. The high-beam indicator on the instrument panel
cluster comes on. Release the lever to return to
normal operation.