GMC 2010 T-Series Owner's Manual page 83

Do not adjust the tilt steering column while driving.
Move the steering wheel
to a comfortable location,
then lock the column in
place by turning the lock
lever all the way down.
Turn Signal/Multifunction Lever
The multifunction lever, located on the left side of the
steering column, includes the following:
G
: Turn and Lane-Change Signals
3
: Headlamps
J
: Cruise Control (if equipped)
Headlamp High-Beam/Low-Beam Changer.
Flash-to-pass.
Information for these features is on the pages following.
3-7