The stepper motor cruise control (SMCC) 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 |
| | The electronic controller completes the following functions: |
| - | Monitors the vehicle speed |
| - | Operates the 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 in order 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 the Cruise fuse through circuit 739
to terminal F of the cruise control module. The cruise control module receives
ground at terminal E, through circuit 1650 and from G119.
When the OFF-ON-R/A switch is moved to the ON position, the battery
voltage is applied through circuit 397 to terminal A of the cruise
control module connector.
If the brake pedal is not pressed, battery voltage is present from
circuit 739 through the cruise control release switch and circuit 86
to the cruise control module terminal D.
If the brake pedal is depressed, battery voltage is supplied from STOP
LAMP Fuse through circuit 140 the stop lamp switch and circuit 17
to the cruise control module terminal G.
When the OFF-ON-R/A switch is moved to the R/A (Resume
/Accelerate) position, the battery voltage is applied through circuit 87
to terminal C of the cruise control module.
With the SET CRUISE button switch pressed, the battery voltage is present
through circuit 84 to the cruise control module terminal B. The cruise
control module terminal K is the speed signal terminal through circuit 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 signals the powertrain control
module (PCM) when the cruise control is engaged through circuit 85.
The PCM then determines the correct shift pattern for the transmission.
The cruise control module terminal H is used by the PCM through circuit 83
in order to inhibit the cruise control when the conditions are inconsistent
with cruise operation.
The PCM inhibits cruise control if the following conditions exist:
| • | The vehicle speed is less than 40 km/h (25 mph). |
| • | The transaxle range switch is in one of the following positions: |
| • | An over/under battery voltage condition exists. |
| • | The engine RPM is high (fuel cut-off). |
