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

The cruise control actuator receives information about operating conditions from the brake pedal position switch, the PCM, and the transmission range switch. The cruise control actuator regulates the throttle position to maintain the selected speed. The control actuator 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 actuator 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 actuator responds by allowing the throttle to close. The transmission range switch sends a "disengage" signal to the control actuator 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 actuator which, in turn, maintains 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 actuator and erases the set speed from memory. If the system is disengaged temporarily by the brake pedal position switch, or transmission range switch, 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 actuator. When you release the position 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 actuator, causing the car to coast. When the desired speed is reached, release the SET switch. This reprograms the system for the new speed.