Mechanics

Alarm System

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Car alarm explanation article with information on how car alarms are triggered and reset. These electronic devices are designed to prevent burglary of the car and warn the owner if a theft attempt is being made. Usually a car alarm will output a high pitched sound when the system is triggered by vibration, close or open of trigger switches, sensing of small and fast change in battery voltage. Modern car alarms also monitor sensors like infrared, microwave, ultrasound or tilting of the vehicle in case of unauthorized towing. Some cars have alarm systems which send out SOS signals in case of breakdown or theft. Alarm systems are also incorporated with navigation systems to increase the security of the car, if the car is stolen, it can be traced by an embedded navigation system. This functionality can also be used to locate lost cars in large parking lots by giving out a chirping sound.

Many times a car alarm can give out a false alarm when it feels vibrations of thunder or a passing truck. Sensors need to be adjusted properly otherwise it can trigger the device even when a person accidentally touches the automobile. There is an increase in the crimes related to theft of vehicles. For people who want security for their cars and want to avoid false alarms you can have a police tracking system installed, many newer cars have this tracking capability built in to the operation of the help/navigation system, like On Star.

These systems come with an additional cost which is to be paid on a regular basis. Most alarm systems utilize a remote controller (key fob); this way a user can disable the alarm from a distance. The remote control feature is very convenient if the system is triggered by a false alarm. Key fob's can integrate a variety of functions, controllers that have the LCD option which can project the image of the part of the vehicle that is under threat by a thief is one example.

When a car alarm becomes unresponsive disconnect the battery to allow the system to "reboot" this will reset the alarm protocol and help the alarm to start working again. Also, if the alarm will not deactivate try locking the car, then using the ignition key unlock the drivers door to reset the alarm system.

Best Practices

  • Keep the car battery in good working order, if a battery is aged it can have a sudden voltage drop which will cause a false alarm.
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AUTHOR


Written by
Co-Founder and CEO of 2CarPros.com
35 years in the automotive repair field, ASE Master Technician, Advanced Electrical and Mechanical Theory.


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Article first published (Updated 2013-11-20)