General System Description

CIRCUIT OPERATION

When the theft deterent system has been turned on, or armed, it will operate automatically when an unauthorized attempt is made to enter the vehicle. This happens when any of the doors are opened, or the forced entry switched on the door locks or any of the luggage compartment locks are closed.

ALARMS

The horn alarm is operated by the horn relay. The coil of this relay is grounded by the solid state theft deterent controller to turn on the horn relay. When the relay contacts close, battery voltage is supplied to the horn. The controller then open the relay coil circuit to turn off the alarms. They will pulse on and off every second for 2 to 4 minutes after the system has been triggered by the tampering or forced entry.


ARMING

The arming sequence begins with the ignition switch turned OFF. This removes battery voltage at terminal K, the ignition input. For vehicles equipped with power door locks, if either door lock switch is moved to lock, and a least one door is open, momentary battery voltage is applied at terminal G, the system arming input. With manual door locks, a similar action occurs when both of the door arm switches are closed which places ground on terminal B at the controller. At the same time, the open door places a ground at terminal J. The arming sequence is completed by closing the last door, which removes the ground signal from terminal J.


CANCELLATION

The arming sequence can be cancelled. With power door locks this is done by moving a front door lock switch to the UNLOCK position before the door is closed to complete the arming of the system. Battery voltage is applied momentarily to terminal M of the theft deterent controller with the door lock switch in UNLOCK. This cancels the arming. With manual door locks the sequence is cancelled if one of the doors is unlocked.

DISARMING

When one of the doors is unlocked with a key, a grounding switch in the front door lock cylinder closes. This grounds terminal H of the controller, the disable input. The system is disarmed and no alarms will operate when a door is opened.

TAMPERING

The alarms are set off when terminal J of the theft deterrent controller, the tamper input is grounded. The door jamb switches close to ground this input when a door is open. In addition, the hatch ajar switch closes when the hatch is opened which grounds terminal C of the theft deterrent controller.