GMC 2003 C4C042 Owner's Manual page 87

Switchbanks
Instrument Panel Switchbank
2-12
This switchbank is located in the center of the
instrument panel.
The switchbank may include marker lamp defeat, high
idle, traction control, heated mirrors, power take
-
rear air suspension, two speed axle (electric), exhaust
-
brake, two speed axle (air), differential lock, rear axle
-
differential lock and inter
vehicle does not have some of the features controlled
by these switches, there will be a blank switch marker in
its place.
For more information, see each of these features in
the Index.
-
off,
axle differential lock. If your