The stepper motor cruise control is a speed control system
which maintains a desired vehicle speed under normal driving conditions. Steep
grades up or down may cause variations in the selected speeds. The system
has the following capabilities:
The cruise control module contains the following components:
| • | An electronic controller -- Monitors the vehicle speed and
operates the electric motor. |
| • | An electric motor -- In response to the controller, the motor
moves a connecting strap that is attached to the cruise control cable. |
The cable moves the throttle linkage to vary the throttle position in
order to maintain the desired cruise speed.
The cruise control module contains a low speed limit which will prevent
a system engagement below a minimum speed, approximately 40 km/h (25 mph).
The module is controlled by mode control switches located on the turn signal
lever. The cruise control is in a standby disabled mode until all the conditions
inconsistent with the cruise control operation are cleared.
The ignition voltage is supplied from fuse 22 through CKT 741
to terminal F of the cruise control module. The cruise control module receives
ground at terminal E, through CKT 1050 and from G117.
When the OFF-ON-R/A switch is moved to the ON position, the battery
voltage is applied through CKT 397 to terminal A of the cruise control
module connector.
If the brake pedal is not pressed, battery voltage is present from
CKT 741 through the cruise control release switch and CKT 86
to the cruise control module terminal D.
If the brake pedal is depressed, battery voltage is supplied from fuse
23 through CKT 140 the stop lamp switch and CKT 17 to the cruise
control module terminal G.
Terminal G needs current flow from through the Center High-Mounted
Stop Lamp (CHMSL) bulbs for cruise to operate (disable) properly. When the
OFF-ON-R/A switch is moved to the R/A (Resume/Accelerate) position, the battery
voltage is applied through CKT 87 to terminal C of the cruise control
module.
With the SET CRUISE button switch pressed, the battery voltage is present
through CKT 84 to the cruise control module terminal B. The cruise
control module terminal K is the speed signal terminal through CKT 389.
In operation, the voltage will oscillate between a high of 4-5 volts
and a low of near ground.
The cruise control module terminal J is used to signal the powertrain
control module (PCM) when the cruise control is engaged through CKT 85.
The PCM will then determine the correct shift pattern for the transmission.
The cruise control module terminal H is used by the PCM through CKT 83
in order to inhibit the cruise control when the conditions are inconsistent
with the cruise operation are present.
The following are the cruise control inhibit criteria:
| • | The vehicle speed is less than 40 km/h (25 mph) |
| • | The transaxle range switch indicates one of the following gears
positions: |
| • | An over/under battery voltage condition exists |
| • | The engine RPM is high (fuel cut-off) |
