Principles of Operation
The speed control system is designed to maintain a selected vehicle speed between 48 km/h (30mph) the maximum limited vehicle speed. The speed control module is integral to the speed control actuator.
Whenever the system is engaged and active, a message from the SJB is sent over the High Speed Controller Area Network (HSCAN) to the Instrument Cluster (IC) to illuminate a speed control set indicator in the IC .
The stoplamp switch is a double pole, double throw switch. It is normally closed to ground. When the brake pedal is applied with the speed control system engaged, the stoplamp switch opens to ground and sends voltage to the speed control actuator, putting the speed control in stand-by mode.
The speed control deactivator switch is used as a redundant signal to the speed control actuator to disable the speed control when the brake pedal is firmly pressed. The switch is normally closed, and opens when the brake pedal is firmly pressed.
On vehicles equipped with a manual transmission, the Clutch Pedal Position (CPP) switch is used to indicate to the speed control actuator when the clutch pedal is engaged. The switch is normally closed, and opens when the clutch pedal is engaged.
The clockspring provides the electrical interface between the steering column wiring and the speed control switches in the steering wheel.
The inputs to the speed control actuator are the:
- Vehicle speed signal
- Speed control switches
- Stoplamp switch
- CPP switch
- Speed control deactivator switch
The outputs of the speed control actuator are the:
- Speed control indicator
- Speed control cable controlled throttle position