240 L4-2320cc 2.3L SOHC VIN 83 B230FD (1993)
on, in the OFF position it is switched off. The RESUME position is used to return to the previous set speed, for example, after braking.
Control unit
This contains the "brain" of the system, which is a microcomputer. It registers the speed when the SET SPEED button is pressed. It responds by
controlling the vacuum motor which regulates the pressure in the vacuum servo and thus the speed of the vehicle.
The set speed is stored in the memory of the control unit either until the system is switched off (by moving the switch on the direction indicator stalk to
OFF or turning the ignition OFF) or until the SET SPEED button is pressed again to change the speed stored in the memory.
Normally the control unit maintains the speed within plus/minus two km/h (1.25 mph). This accuracy is achieved by actuating the vacuum pump or
vacuum valve at intervals as short as 40 milliseconds.
The control unit has several safety functions to prevent malfunction in the event of a fault developing in the system.
The speed must be above 35 km/h (22 mph), the control must be set to ON and the SET SPEED button must be pressed for the control unit to work
and for its relay to feed current to the vacuum pump and to connect it to ground.
The control unit then monitors current supply and controls the vacuum pump and vacuum valve. The control unit does not activate the relay in case
vacuum pump and vacuum valve are short-circuited to ground.
As a further safety measure, the system is disengaged during rapid braking, even if both brake valve and brake lights are inoperative.
Vacuum pump
