Cruise Control: Description and Operation

How the Circuit Works

The cruise control system uses mechanical and electrical devices to maintain the car's speed at a setting selected by the driver.

System Description
The cruise control unit receives command signals from the cruise control switch and the cruise control Set/Resume/Cancel switch. With the ignition switch in ON (II) or START (III), voltage is provided to the cruise control unit and cruise control switch through fuse 6 (in the driver's under-dash fuse box). When you push the switch to ON. power is provided to the cruise control unit and the brake pedal position switch.

The cruise control unit receives information about operating conditions from the brake pedal position switch, the PCM or ECM, and the the transmission range switch (A/T) or clutch pedal position switch (M/T). The cruise control unit then sends signals to the cruise control actuator which regulates the throttle position to maintain the selected speed. The control unit compares the actual speed of the car to the selected speed, and then opens or closes the throttle as necessary to match the selected speed.

The brake pedal position switch releases the system's control of the throttle at the instant you press on the brake pedal. The switch sends a signal to the control unit by removing power from the normally closed brake input (GRY wire), and providing power at the normally open brake input (WHT/BLK wire). The control unit responds by allowing the throttle to close. The transmission range switch (A/T) or clutch pedal position switch (M/T) sends a disengage" signal to the control unit that also allows the throttle to close.

The cruise control system will set and automatically maintain any speed above 25 mph (40 km/h). To set it, make sure the main switch is on and the switch indicator is on. Then, after reaching the desired speed, press the SET switch. This sends a "set" signal to the cruise control unit which, in turn, controls the cruise control actuator to maintain the set speed.

When you push the SET switch and the cruise control system is on, the cruise control ON indicator lights up.

You can cancel the cruise control system by pushing the cancel switch or by turning the main switch off. This removes power to the control unit and erases the set speed from memory. If the system is disengaged temporarily by the brake pedal position switch, or transmission range switch (A/T) or clutch pedal position switch (M/T), and the car's speed is still above 25 mph, press the RESUME switch: the car will automatically return to the previously set speed.

For gradual acceleration without pressing the accelerator pedal, push the RESUME switch and hold it there. This will send an "acceleration" signal to the control unit. When you release the switch, the system will be reprogrammed for the new speed. To slow the car down, push the SET switch in and hold it there. This sends a "deceleration" signal to the control unit, causing the car to coast. When the desired speed is reached, release the SET switch. This reprograms the system for the new speed.