Circuit Operation

The Stepper Motor Cruise Control (SMCC) is a speed control system which maintains a desired vehicle speed under normal driving conditions. However, steep grades up or down may cause variations in the selected speeds. 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, approximately 25 mph (40 kph). The module is controlled by mode control switches located on the Turn Signal Lever. Cruise Control is in "Standby Disabled" mode until all conditions inconsistent with Cruise Control operation are cleared.

With the Ignition Switch in "RUN," battery voltage is applied through CKT 741 to terminal "F" of the Cruise Control Module. When the Cruise Switch is moved to the "ON" position. battery voltage is applied through CKT 397 to terminal "A" of the Cruise Control Module Connector. If the brake pedal is not depressed, battery voltage is present through CKT 86 to module terminal "D." If the brake pedal is depressed, battery voltage is present through CKT 17 to module terminal "G." Terminal "G" must see current flow (through the Center High Mounted Stoplamp (CHMSL) bulbs) for cruise to operate (disable) properly. When the Cruise Switch is moved to the "R/A" position, battery voltage is applied through CKT 87 to terminal "C" of the module. With the Set Switch depressed, battery voltage is present through CKT 84 to module terminal "B." Cruise Control Module Connector terminal "K" through CKT 389 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 from G117 through CKT 1050 is at module terminal "E." Terminal "J" through CKT 85 is used to signal the Powertrain Control Module (PCM) when Cruise Control is "engaged." The PCM will then determine the correct shift patterns for the transmission. Terminal "H" through CKT 83 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 vehicle speed is less than 25 mph (40 kph).
^ 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 cut-off).