Cruise Control: Description and Operation

OPERATION
The Speed Control Amplifier controls vacuum through the modulating valve to the Speed Control Servo Motor. The Servo Motor moves the throttle through the Actuator cable.

For the Speed Control System to operate, the engine must be running and the vehicle speed must be greater than 30 mph. Pressing the ON switch of the Speed Control Switch Assembly turns on the system.

Pressing and releasing SET/ACCEL or COAST sends a command to hold the present speed. This speed becomes the set speed. Using the Vehicle Speed Signal, the Speed Control Amplifier controls vacuum at the Servo Motor to keep the vehicle at the set speed.

Pressing and holding SET/ACCEL speeds up the car. The vehicle's speed increases while SET/ACCEL is depressed. Releasing SET/ACCEL gives the system an new set speed to maintain. Vehicle speed may also be increased by depressing the accelerator until the higher speed is reached, then pressing and releasing the SET/ACCEL.

Pressing and holding COAST slows down the vehicle. The vehicle speed decreases while COAST is depressed. Releasing COAST gives the system a new speed to maintain.

Pressing OFF turns off the system. The system is also turned off when the Ignition Switch is turned off. Depressing the brake pedal cancels the speed control. The Vacuum Dump Valve also operates when the brake pedal is depressed. This serves as a backup device to release the servo.

When the system has been cancelled by depressing the brake pedal, the last set speed may be resumed by pressing RESUME. This feature will not work if OFF has been depressed or when the vehicle speed is below 30 mph.