Originally Posted by the1boss
The alarm goes off when the car has been locked and the alarm has been enabled. After awhile the alarm just seems to go off. I 've sat there and watched/heard it go off for no apparent reason. Any ideas out there as to why this might be happening? As always, any help would be greatly appreciated
As far as I can recall, the alarm is triggered by intrusions only (i.e. there'* no shaker switch, glass-breakage detector or voltage sensor). It'* a logic circuit that triggers the alarm if the car is locked via either the internal door switch or a key on the outside, followed by a door opening. (It shouldn't open, because the last known event was locking the car.) The trunk lock has a tampering switch on it as well, to trigger if the lock cylinder is rotated or removed.
The security system detects you locking the car one of three ways: Pressing the Lock switch on the inside and closing the doors, or closing the doors and using a key on the outside, or closing the doors and using your keyless remote to lock it. (Not sure if you have to close the doors first if you're using the remote.)
You can fool the car into locking it without setting the alarm by manually locking the doors (i.e. with your finger on the door lock slide) and then closing them, or by closing the doors and _then_ pressing the Lock switch inside the car (i.e. it assumes someone is remaining in the car), so the car is locked up but the security system doesn't arm itself.
But assuming the system is armed, there are only two ways to disarm it again: Pressing the Unlock button on your remote, or by using your key in the door lock. Turning the door lock grounds a light green wire which signals the entry system to unlock all doors, and disarms the security system.
So basically you have me stumped right now, but maybe something above might help you pin this down.