Chevrolet 2012 Colorado Owner's Manual page 222

If the vehicle has four-wheel drive,
you can send the engine's driving
power to all four wheels for
extra traction. To get the best
performance out of four-wheel
drive, you must be familiar with its
operation. Read this section before
using four-wheel drive. You should
use two-wheel drive high for most
normal driving conditions.
The transfer case buttons are
located to the right of the steering
wheel on the instrument panel.