Circuit Operation

The Stepper Motor Cruise Control (SMCC) is a speed control system which maintains a desired vehicle speed under normal driving conditions. The system has the capability to CRUISE, COAST, RESUME SPEED, ACCELERATE, TAP-UP and TAP-DOWN.

An Electronic Controller and Electric Motor are contained in the Cruise Control Module. The Controller monitors vehicle speed and 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 to vary throttle position in order to maintain the desired cruise speed. The Cruise Control Module contains a low speed limit which will prevent system engagement below a minimum speed, about 25 mph. The module is controlled by mode control switches located on the Multi-Function Lever. Cruise Control is in "Standby Disabled" until all conditions inconsistent with Cruise Control operation are cleared.

With the Ignition Switch in "RUN," battery voltage is applied to terminal "F" of the Cruise Control Module. When the Slider Switch is moved to the "ON" position, battery voltage is applied to terminal "A" of the Cruise Control Module. If the brake pedal is not depressed, battery voltage is present at module terminal "D". If the brake pedal is depressed, battery voltage is present at module terminal "G". Terminal "G" must see current flow [through the High Mounted Stop Lamp (HMSL) bulbs for cruise to operate (disable) properly. When the Slider Switch is moved to the "ON" position, battery voltage is applied to terminal "C" of the module. With the Set Switch depressed, battery voltage is present at Cruise Module terminal "B". Cruise Module Connector terminal "K" is the speed signal terminal. In operation, voltage will oscillate between a high of 4 to 5 volts and a low of near ground. Ground is at module terminal "E". Terminal "J" is used to signal the Powertrain Control Module (PCM) when Cruise Control is "engaged." The PCM will then determine the correct shift pattern for the transmission. Terminal "H" is used by the PCM to "inhibit" Cruise Control when conditions "not consistent" with cruise operation are present. These are the Cruise Control Inhibit Criteria.

The PCM will "Inhibit" Cruise Control:
^ When VSS is less than 25 mph.
^ When "PARK," "REVERSE," "NEUTRAL," or "1st GEAR" is indicated by the Transaxle Range Switch.
^ When an over/under battery voltage condition exists.
^ With low Engine RPM.
^ With high Engine RPM (fuel cutoff).