Cruise Control Systems: Operation

When switch is placed in "ON" position and "SET" button is depressed, speed sensor sends a signal to control unit. This informs control unit of vehicle speed. Vacuum pump increases vacuum to move diaphragm in vacuum regulator, which acts on the throttle lever to maintain preselected vehicle speed. Speed sensor senses vehicle speed changes and sends a signal to control unit. Control unit sends signals to vacuum motor to reduce or increase vacuum to maintain preselected vehicle speed.