Buick Enclave: Description and Operation
STEERING WHEEL AND COLUMN DESCRIPTION AND OPERATION
The steering wheel and column has 4 primary functions:
- Vehicle steering
- Vehicle security
- Driver convenience
- Driver safety
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, found on 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 ignition switch
- The steering column lock
- The ignition cylinder
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 turn signal switch
- The hazard switch
- 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
- The HVAC controls
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.
Ignition Lock Cylinder Control Actuator
If the vehicle is equipped with a floor mounted console gear shift, it has a ignition lock cylinder control actuator system in the steering column. The ignition lock cylinder control actuator's purpose is to prevent the ignition key from being turned to the OFF position when the transmission is in gear and the vehicle may still be moving.
The column ignition lock system consists of a ignition lock cylinder control actuator and a park position switch that is located in the A/T shift lock control switch. The ignition lock cylinder control actuator contains a pin that is spring loaded out to mechanically prevent the ignition key cylinder from being turned to the lock position when the vehicle transmission is not in the Park position. If vehicle power is lost, and/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.
STEERING WHEEL CONTROLS DESCRIPTION AND OPERATION (POWER TILT AND TELESCOPE)
Tilt/Telescoping Switch Operation
The tilt/telescoping steering column has a four-position switch which may be used to adjust the position of the steering wheel in or out which is telescope and up or down which is tilt. The position of the column may be changed as follows:
- Press the switch up to tilt the column up.
- Press the switch down to tilt the column down.
- Press the switch forward and the column moves toward the front of the vehicle.
- Press the switch rearward and the column moves toward the rear of the vehicle.
The memory seat module (MSM) receives inputs from the tilt/telescope switch to manually move the column to a desired position. Pressing the control switch sends an input to the MSM. The MSM receives an input and actuates the corresponding column motor.
Pressing the switch momentarily in either the UP or DOWN or IN or OUT position and releasing within 0.5 seconds, causes the column to advance slightly in the corresponding direction then stop. This feature allows fine control of the steering column position in each direction. If the switch is pressed and held for longer than 0.5 seconds, the column advances slightly in that direction, pauses, then resumes movement as long as the switch is held.
Motors
Both the tilt and telescoping motors are reversible. For example, the tilt motor moves the column both up and down. When the MSM receives an input to move the column up, the MSM supplies battery positive voltage and ground to the tilt motor in order to move the column up. When the MSM receives a column down input, the MSM supplies battery positive voltage and ground to the same motor, but with a reverse polarity. When the voltage polarity is reversed, the motor runs in the opposite direction and moves the column down.
Position Sensors
Two position sensors are used by the MSM to store column positions in memory and to return the column to the stored memory positions. The MSM provides a 5-volt reference voltage and a ground to both the tilt and telescoping position sensors. The sensor feedback circuit voltage varies from 0.25-4.75 volts. Each sensor is mounted to its corresponding motor cable assembly. When the motor rotates its cable, the resistance of the sensor varies. The MSM monitors the feedback voltage to determine the column position via the tilt and telescoping position sensor input circuits. When an entry or exit position is saved, the MSM stores the column positions by recording each position sensor's feedback voltage. When an entry or exit position is commanded, the module moves the motors until all the position sensor feedback voltages equal the feedback voltages stored in memory.
Tilt/Telescoping Memory
Memory settings and the personalization of steering wheel positions are available with the tilt/telescoping steering column. The data stored consists of entry positions and exit positions. The entry position is the position that the steering column moves in when the ignition is turned ON. The exit position is the direction that the steering column moves in when the ignition is turned OFF and the driver's door is opened.
An initial memory setting is set in the MSM at the assembly plant. This setting may be changed to suit the customer at the time of purchase or at anytime in the future.
Entry/Exit Personalization
The MSM stores personalization information. The driver information center (DIC) is used to enable and disable the personalization feature in the MSM. A serial data message is sent to the MSM, by the DIC, which specifies that the MSM enable the personalization feature until disabled again using the DIC.
The memory seat module can store 6 possible positions: 3 entry positions and 3 exit positions.
- Driver 1 exit position, set using the memory switches
- Driver 2 exit position, set using the memory switches
- Default exit position which is all forward, all up, with no memory position set
- Driver 1 entry position, set using the memory switches
- Driver 2 entry position, set using the memory switches
- Last known driver entry position which is when the ignition is turned ON by an unknown driver
Memory Setting
When the driver door switch assembly (DDSA) receives inputs from the memory function switch, the steering column personalization positions may be recorded for one or two different drivers. Once a steering column driving entry or exit position is adjusted by the driver it must be set in memory. To record a position, the driver must press the SET MEMORY button, which is followed by a chime to acknowledge that input. Within 5 seconds, either the MEMORY 1 or MEMORY 2 button must be pressed. When the DDM receives these inputs, it sends a serial data message to the MSM. The MSM records the feedback voltages from the column position sensors for that driver. A single chime is sounded to acknowledge that the position was recorded.
To record a second position, the second driver must press the SET MEMORY 2 button, after they have made the appropriate adjustments and the process continued.
Memory Personalization Recall
When the driver presses the MEMORY 1 or MEMORY 2 button, the DDSA receives the input and a single chime is sounded. The DDSA sends a serial data message to the MSM indicating which driver memory setting has been selected. The MSM applies both battery positive voltage and ground to the column motors until all the column position sensor feedback voltages equal the feedback voltages stored in memory for the appropriate driver.
When a keyless entry transmitter is used to unlock the vehicle doors, the remote function actuator (RFA) module communicates which driver key fob performed that command. The MSM receives the unlock command via a serial data message from the RFA module.
STEERING WHEEL CONTROLS DESCRIPTION AND OPERATION (HEATED STEERING WHEEL)
Heated Steering Wheel
The heated steering wheel system consists of a heated steering wheel, a heated steering wheel switch and a steering wheel heat module. The heated steering wheel includes non-serviceable heating elements and a temperature sensor. The heating elements and sensor are located around the entire of the rim of the steering wheel. The heated steering wheel switch is located in the left steering wheel control switch assembly. The steering wheel heat module is located at the left side of the steering wheel center hub. When the switch is pressed, the switch signal circuit is grounded and the heat module turns the heated steering wheel on. The system then remains on until the customer turns it off. The wheels normal operating temperature is 32ºC (89.6º F). The wheel takes approximately 3 to 4 minutes to reach the normal operating temperature. The wheel will take longer to heat up if the vehicle temperature is below -21ºC (-5.8ºF). The built-in temperature sensor provides input to the controller to limit the temperature to the normal operating temperature. The wheel will not operate if the vehicle temperature is at or above 32ºC (89.6ºF).
SPECIAL TOOLS AND EQUIPMENT
SPECIAL TOOLS
