SAFETY FEATURES OF
SCS CRUISE CONTROLS
FOUR SEPARATE SAFETY FEATURES ON THE BRAKE SYSTEM ALONE
1. Brake light switch signals the Cruise Control Electronic Module when the
brake pedal is depressed. This causes the electronics to release the throttle
and return the engine to idle.
2. The Electronic Module must be connected into the brake light switch for the
Cruise Control to operate. Should the wire from the Electronic Module to the
brake light switch become disconnected, the Electronic Module assumes that
the brakes are applied and returns the engine to idle.
3. Because the above features are dependent on the brake circuit functioning,
should the brake light system fail. It would then be impossible to operate the
Cruise Control.
4. The Cruise Control continuously monitors the speed of the car while cruising.
Anything that will cause the car to lose 10 m.p.h. in one second will shut off
the Cruise Control. Therefore, the system can be deactivated just by slowing
the car with the brakes. We also shut off the Cruise control if the system sees
an increase in speed of 10 m.p.h. per second, as it might if the wheels were
to spin on an icy road.
ADDITIONAL SAFETY AND OTHER FEATURES OF THE SCS CRUISE CONTROL
1. VACUUM: All valves in the system are built so that their normal position will
cause the car to return to idle. For example, the vacuum valve is held closed
by a spring, while both the safety and vent valves are held open by springs. If
any of the three valves fail, or if there is a power loss, the unit will not operate
at all.
ELECTRONIC: The throttle is held open with an electro magnet. Should
power to the system fail, the magnet will release and return the throttle to idle.
2. Power for the valves or magnet is continuously monitored by the
microcomputer. If the key is turned off even momentarily, the unit will shut off
and not resume cruise until it is reset.
3. The microcomputer monitors the speed of the vehicle, and the unit will not
cruise below 25 m.p.h.
4. The “Off” button is wired to override all other controls.
5. On some applications with manual transmissions, a separate switch on the
clutch turns the Cruise Control off anytime the clutch is depressed.
6. A “power on reset” sets all stored valves in the circuit to zero everytime the
unit is turned on. This is a timing function and the unit will not operate until
this has been done.
7. A “watch dog” circuit monitors the operation of the microcomputer. Should
anything go wrong with the microprocessor, the “watch dog” circuit will shut
the system down.
8. Amazingly enough, the majority of the electronic components of our cruise
control system are for safety and reliability instead of function. Our Cruise
Control will operate very, very well without many of these components. On
the circuit board itself, most of the resistors and capacitors are for protection
against transient voltages that could possible be encountered on the car
under extreme conditions. Every board has its own power supply so that the
integrated circuit can operate at 5.1 bolts, which is well below automotive
voltage and assures a continuous, even supply of power, the interruption of
which otherwise could cause problems.
9. The entire Cruise Control system is designed in a manner with normally open
switches and normally open valves so that should a failure occur, this failure
will completely prevent the Cruise Control form operating at all, rather than
causing it to operate in a faulty manner.
10. When designing the Cruise Control, we worked with one of the largest
manufacturers of electronic components in the world and developed an
integrated circuit designed exclusively for cruise control application. This
lowered our parts count which improved reliability and also enabled us to start
from the point where we had a product that was completely safe and allowed
us to design additional safety features into the unit.
11. Due to our long experience with O.E. accounts in the Automotive industry, we
believed that the safest product would be the one that was the simplest both
in design and installation, and one that had the fewest components to fail.
This was one reason why on Import applications, we attach our vacuum
motor to the top of the accelerator pedal arm, where the linkage is much less
complicated than it is at the carburetor, and where components are protected
from the dirt and weather which could cause them to stick or bind. It was this
innovation which was one of the prime considerations in Chrysler’s choice of
SCS, as the first company to ever supply them with an Electronic Cruise
Control.
Another prime consideration of safety is the reliability of outside purchased components used.
Wherever we have chosen our Cruise Control components, we have used proven parts used in
high volume by O.E. automotive manufacturers. These parts are tested extensively by O.E.
engineering and quality control departments and the are tested 100% in our factory.
