Security Alarm System
The security alarm system is armed automatically after the doors, hood, and trunk are closed and locked. For the system to arm, the ignition switch must be off, the key must be removed, and the MICU must receive signals that the doors, hood, trunk are closed and locked. The alarm can be disarmed at any time by unlocking the driver's door with the key or pressing the UNLOCK button on the remote transmitter.
When everything is closed and locked, the only inputs that are grounded, and have 0 volts, are the driver's door lock knob switch (LOCK position), and the audio-HVAC display unit. In other words, all of the other switches are open, including the key cylinder switches, and they have about 10 V. The security indicator in the gauge control module begins to flash immediately after the vehicle is completely closed and locked. 15 seconds after the doors are locked with the key the security system arms and the security indicator flashes on for a shorter amount of time than before. If the security indicator does not flash, the system is not arming. A beep to confirm the security alarm system is armed will sound if the LOCK button is pressed a second time within 5 seconds.
If one of the switches is misadjusted or there is a short in the circuit, the security system will not arm. As long as the control unit continues to receive a ground signal, it senses that the vehicle is not closed and locked, and the system will not arm. Conversely, a switch that is slightly misadjusted can cause the alarm to sound for no apparent reason. In this case, a significant change in outside air temperature, the vibration of a passing truck, or someone bumping into the vehicle could cause the alarm to sound. There is no glass breakage or motion detector feature.
If anything is opened or improperly unlocked after the system is armed, the control unit receives a ground signal from that switch, and the 10 V reference drops to 0 V. If the audio-HVAC display unit is disconnected, the input loses its ground, and the input voltage goes to 10 V. The system sounds the alarm when any of these things occur:

- A door or the trunk is forced open
- A door is unlocked without using the key or the remote transmitter
- The hood is opened
- The audio-HVAC display unit is disconnected

When the system sounds the alarm, the horns sound and the exterior lights flash for 2 minutes. The alarm can be stopped at any time by unlocking the driver's door with the key or by pressing any button on the remote transmitter.