does anybody know if there is a alarmsystem on a '84 vette?? And when there is one, how does it works?
The doors and rear hatch are equipped with protective switches which will trigger the alarm, if opened while the system is in the armed condition. The switches are located in both door hinge pillars and at the hatch opening. Each door lock is equipped with a tamper switch which will trigger the alarm if the lock cylinder is tampered with in any way different from the normal mode of operation.
The Electronic Theft Deterrent System (UTD) is electrically protected by a 10 amp fuse.
The controller is all electronic and is serviced on an exchange basis. The controller operates in two stages; first is the “Armed” stage, and the second is the “Activated” stage. These stages will be explained separately.
After the ignition is turned off, the system may be armed at either opened door by:
[1.] With power door locks: Activating the electric door lock switch to the lock position.
[2.] With manual door locks: Depressing the door lock button to the lock position. When the last door is closed, (after a 5 second delay) the system arms.
The system is disarmed by unlocking the driver's door with the key or by turning the ignition on. Alarm shut down is accomplished only by unlocking the door with the key. If the driver wants to prevent arming the system after using the “Door Lock” rocker switch, the switch can be moved to the unlock position before closing all doors. He may also cancel the arming process by rotating the ignition switch to the "ON" position, then back to lock. Rotating the ignition switch will not cancel the alarm once it is activated. The doors may be locked mechanically using the door key without arming the system. The ignition key in the ignition lock can only disarm the system, (before the alarm is activated).
Automatic Shut Down
Once the alarm has been activated, alarm will continue to operate for a period of three-seven minutes. At the end of the time out period, the alarm will automatically shut off to conserve battery power and, if the locks have not been damaged, the system will rearm itself. However, once the system has been activated, the starter interrupt relay will remain energized until the proper disarming sequence is initiated.
VATS uses a special ignition key which allows the VATS module to:
Without a signal response from the VATS module, the ECM will not allow fuel injection. VATS protection is present even after the present alarm system is defeated, or if the car is left unlocked. Use of the VATS system requires no changes in operation (arm-disarm) over the 1985 system.
[1.] Signal the ECM.
[2.] Close the starter circuit.
VATS SYSTEM OPERATION
The VATS system operates to prevent starting (cranking) of the vehicle, and fuel delivery to the engine, using any key other than the special electrically coded ignition keys supplied with the vehicle at new car delivery. The VATS system operates independently of the present UTD alarm system. The system is completely passive and requires no active involvement from the operator to function. When the operator turns the ignition “OFF”, cranking and engine fuel delivery are automatically disabled. Inserting the properly encoded key into the ignition signals the VATS module to permit cranking and fuel delivery to the engine. If the key used does not have the proper electrical coding (unauthoized starting), the VATS module will reset for 2 to 4 minutes (crank and fuel disabled) and will not permit starting during this period even with the proper key. To start the vehicle, the key must have the correct mechanical and electrical coding. The ignition lock cylinder contains electrical contacts used to "read" the ignition key.
If the ignition key is lost and the mechanical code is unknown, the mechanical code must be determined using current key replacement procedures. The mechanical code must be cut on a blank designed for use with the VATS system. The key must be electrically coded to match the code of that particular VATS equipped vehicle. Electrical coding requires two steps. A special decoding tool is used to determine the code required, the proper code is then programmed into the key.
PASS-Key Theft-Deterrent System
Corvette pioneered the use of PASS-Key, originally known as VATS (Vehicle Anti-Theft System) on Chevrolet passenger cars. The system, introduced in 1986, relied on a pellet embedded in the ignition key. If an improper key was used, the system cut off the starter and the fuel injectors, immobilizing the Corvette. The VATS system is credited with reducing Corvette thefts by 45 percent in the first year alone. Theft-deterrent systems are common among many Chevrolet passenger cars today, including a new system called PASSLock on some Chevrolets, that offers similar protection without the need for a key-mounted resistor pellet.