Why does the car alarm keep sounding off?

Your car alarm is sounding off again; you go out to check, but again, your car stand still on the parking lot. You look around and can’t get any clues of what has triggered it. After several times, you just ignored it and the neighborhood is annoyed, your neighbors are livid. There’s definitely something wrong with the alarm, but what on earth is it? If you want to find the answer yourself, you can follow the below directions and have a try. Good luck!
1. Find the shut-off switch for your alarm system. When your alarm was installed, the installer most likely equipped it with a shut-off switch to allow you to turn off your alarm system at any time. The shut-off switch is usually located below your steering wheel near your feet and is hidden so that thieves can’t find it. Your installer should have shown you where it is. You may have to hold it down for three or four seconds for the system to shut down.
2. Disconnect the fuse on the alarm in your fuse box. The fuse for the car alarm should be marked on the box, or you may have to look at your car owner’s manual to figure out which fuse to remove.
3. Try resetting the alarm system. One possibility is to put the key in the car door, turn to lock the door, then turn again to open it in order to reset the alarm. Other tricks and processes could help you reset your alarm system, depending on your car model. See the Resources section for another method for resetting your car alarm.
4. Disconnect the battery. This option is a last-case scenario. Turn off your car and remove the keys. Two cords that power your car run up to the top of the battery where they are screwed on (think of the positive and negative connectors you use when you jump start your car). Use a wrench to unscrew the side nut of each connector. (Do the negative side first, and when you reconnect the battery put the negative side back on first.) You should be able to lift the connector up and off of the battery. This method is most helpful when you have a car alarm that is going off at night, or when you are not actively using the car.
Tips & Warnings
Always use extra care when handling your car battery’s connectors. Wear rubber gloves for added protection. Keep in mind that when you reconnect your car battery, the alarm will probably start to go off again immediately. You also have to be forewarned that disconnecting the battery could affect your car’s computer system and possibly create further problems.