The steering wheel and column has 4 primary functions:
Vehicle Steering
The steering wheel is the first link between the driver and the vehicle.  The
steering wheel is fastened to a steering shaft within the column. At the  lower end
of the column, the intermediate shaft connects the column to the  steering gear.
Vehicle Security (Some Vehicle Models)
Theft deterrent components are mounted and designed into the steering  column.
The following components allow the column to be locked in order to  minimize theft:
|     •  | The steering column lock | 
 
Driver Convenience
The steering wheel and column may also have driver controls attached  for convenience
and comfort. The following controls may be mounted on or near  the steering wheel
or column.
|     •  | The headlamp dimmer switch | 
 
|     •  | The wiper/washer switch | 
 
|     •  | The horn pad/cruise control switch | 
 
|     •  | The redundant radio/entertainment system controls | 
 
|     •  | The tilt or tilt/telescoping functions | 
 
|     •  | The navigation/OnStar® features | 
 
Driver Safety
The energy-absorbing steering column compresses in the event of a front-end
 collision, which reduces the chance of injury to the driver. The mounting  capsules
break away from the mounting bracket in the event of an accident.
Park Lock Solenoid
If the vehicle is equipped with a floor-mounted console gear shifter,  an added
safety feature is an park lock solenoid system in the steering column.  The park lock
solenoid system prevents the steering wheel from being locked  when the transmission
is in gear and the vehicle may be moving. The column  ignition lock system consists
of a park lock solenoid and  a park switch, that is located in the A/T shift lock
control switch.  The park lock solenoid contains a spring-loaded pin that
mechanically  prevents the ignition key cylinder from being turned to the Lock position
 when the transmission is not in the Park position. If vehicle power is lost  or the
transmission is not in the Park position, the operator will not be  able to turn the
ignition key to the Lock position and will not be able to  remove the ignition key
from the column.