The stepper motor cruise control (SMCC) is a speed control
system which maintains a desired vehicle speed under normal driving conditions.
However, steep grades may cause variations in the selected speeds. The system
has the following settings:
The cruise control module contains an electronic controller and an electric
motor. The controller monitors the speed of the vehicle and operates the motor.
In response, the motor moves a connecting strap that is attached to the cruise
control cable. The cable moves the throttle linkage which varies the throttle
position and maintains the desired cruise speed. The cruise control module
contains a low speed limit which prevents engagement of the system below
a minimum speed, approximately 25 mph.
The mode control switches are located on the multi-function turn signal
lever. Cruise control is in Standby Disabled mode until all conditions which
are inconsistent with cruise control operation are cleared.
With the ignition switch in RUN, battery voltage applies to terminal F
of the cruise control module. When you move the slider switch to the ON position,
battery voltage applies to terminal A of the cruise control module
connector. If the driver of the vehicle does not depress the brake pedal,
battery voltage is present at module terminal D. When the driver presses
the brake pedal, battery voltage is present at module terminal G.
Terminal G must see current flow through the center high mounted stoplamp
bulbs in order for cruise to operate (disable) properly.
When the driver moves the slider switch to the R/A position, battery
voltage applies to terminal C of the module. With the Set switch pressed,
battery voltage is present at module terminal B.
Cruise control module connector terminal K is the speed signal
terminal. In operation, voltage will oscillate between a high of 4 to 5 volts
and low of near ground. Cruise Control Module terminal E is ground.
Terminal J signals the PCM when cruise control is engaged. The
PCM determines the correct shift pattern for the transmission.
The PCM uses terminal H in order to inhibit cruise control when
any of the following conditions, which are inconsistent with cruse operation,
occur:
• | Vehicle speed is less than 25 mph |
• | When the park/neutral position (PNP) switch indicates the following
gears: |
• | When an under battery condition or an over battery condition exists |
• | With high engine RPM (fuel cut-off) |