System Description - Burglar Alarm System

BURGLAR ALARM SYSTEM
The burglar alarm system is armed automatically after the doors, hood, and trunk are closed and locked.

The system is set off when any of these things occur:
- A door is forced open.
- A door is unlocked without using the transmitter.
- The trunk lid is opened without using the key.
- The hood is opened.
- The engine starter circuit and battery circuit are bypassed by breaking the ignition switch.

When the system is set off, the alarm (siren) sounds and the hazard lamp flash for about two minutes or until the system is disarmed by unlocking with the transmitter.

For the system to arm, the ignition switch must be off and the key removed. Then, the ETACS module must receive signals that the doors, hood, and trunk lid are closed and locked. When everything is closed and locked, none of the control unit inputs are grounded.

The door switches, hood switch and trunk lid switch are all open. Immediately after locking the doors with the remote transmitter, the system arms.

If anything is opened or improperly unlocked after the system is armed, the ETACS module gets a ground signal from that switch, and the system is set off.

If the trunk is opened using the key after the system is armed, the doors and hood continue to be in the arm state and the system will not be set off. Then after the trunk is closed, the trunk hold arm state.

If one of the switches is misadjusted or there is a short in the system, the system will not arm. As long as the ETACS module continues to get a ground signal, it thinks the vehicle is not closed and locked and will not arm.

An alarm that sounds for no apparent reason may have been set off by a switch that is on the threshold of misadjustment. In this case, it may only take a significant change in outside temperature, the vibration of a passing truck, or someone bumping into the vehicle to make the alarm sound.