not be the most advanced system money can buy, it should offer a good level of protection and will have been tested and approved for your model of car.
If your car did not come with an alarm fitted, you need to decide whether you are going to buy a simple system that you can fit yourself, or pay an expert to fit something more sophisticated. Be warned, the cheaper and simpler it is to fit, the easier it will be for a thief to get around. For example, air-pressure-sensitive devices which you lock over the steering wheel are advertised as having a siren so piercing that the thief will be unable to drive because of the noise — in fact, thieves can rip these off and throw them out of the window in a matter of seconds. Alarms which use the car’s horn are also a doddle for thieves: the wires are usually fitted behind the engine grille — snip them and the alarm stops. If you’re on a tight budget, it’s probably best to opt for an alarm which can be expanded; buy the basic unit to start with and add the rest as and when your finances allow.
Go for the noisiest siren you can get. To make sure that thieves can’t silence the alarm by getting under the car and cutting the battery cable, get a system with a back-up battery. The method whereby you can switch off the alarm, should the need arise, varies: some use a hidden switch or a key in the siren unit, but the best are operated by remote control (which may also operate the car’s central locking). But be warned: these remote locking devices are not without risk. Illegal receivers, known as ‘grabbers’ can be used by thieves to copy your code as you lock the car; the code is then copied on to their own remote and transmitted to open your car. A grabber’s range is limited, so be suspicious of anyone standing close by holding a small box when you lock the car. The best remote control systems foil grabbers by automatically changing their code each time they are operated.
Remember to change the batteries of your remote control as often as the manufacturer recommends, or you won’t be able to deactivate the alarm.
Alarms can detect an intruder in a variety of ways, depending on which sensors they are fitted with:
Direct contact sensor. Electronic sensors in the doors, boot/hatch, bonnet trigger an alarm when forced open. This system won’t be activated if thieves smash a window to steal your radio.
Current and voltage-drop sensors detect changes in the car’s electrical system. If your vehicle is fitted with a cooling fan which runs even when the engine has been switched off, this system cannot be fitted. Again, there is no protection against a thief smashing the window.
Ultrasonic sensors detect changes in air pressure within the car and will trigger the alarm if someone smashes a window or gets in the car. The downside is that if it’s windy outside or if a passing vehicle creates a strong breeze, air coming through the vents can set off the alarm, so you have to remember to close all interior vents, windows and sunroof when you park the car (if you have a convertible with a soft roof, opt for another type of alarm altogether). Some sensors can be switched off, or the sensitivity adjusted — but don’t turn it down too far or the alarm may not go off when someone tries to break in.
Microwave sensors detect solid objects which pass through beams directed past all points of entry. Microwave systems are expensive, but less prone to false alarms. They are also suitable for convertibles, as even with the roof down the beams will trigger the alarm if anyone reaches inside the car.
Shock sensors detect sudden shocks, like someone trying to smash their way in or vandalize the car. The sensitivity needs to be adjusted to avoid false alarms every time another vehicle passes by.
Tilt sensors react to the car being lifted, thus preventing anyone loading the car on to another vehicle or towing it away.
Other features worth having include a panic button, so that if you are attacked when in or near your car the alarm will sound; a status monitor, to notify you (usually by means of the LED display) that the alarm has been activated while you were away from the car; and finally, perhaps the most useful secondary feature of all, engine immobilization to disable the electrics and prevent the car starting when the alarm goes off.
The latest innovation in alarms is the use of specially formulated, non-toxic smoke. In the event of an attempted car-jacking or attack, there is a 35-second countdown. If the owner does not reset the system, the engine starts to misfire and progressive immobilization begins: lights flash, the horn sounds and the engine stops completely. Finally a dense smokescreen is pumped into the car. The car remains immobilized until the correct PIN number is entered.
Whichever system you choose, make sure there is a good visual deterrent such as a flashing light visible from outside the car. And, most important of all, remember to switch your alarm on — even if you’re only leaving the car for a couple of minutes.
There are two main types of immobilizer: mechanical (for example, crook locks and clamps which physically prevent the operation of controls such as the steering wheel or gear lever) and electronic. An electronic immobilizer is wired into the car’s electrics to prevent the engine from being started. (A third form of immobilizer is the steering column lock, fitted as standard in all cars built since 1972. This operates when the key is removed from the ignition, and the steering wheel is turned until it clicks.) Of these, the electronic immobilizer is the most difficult for thieves to get around, because the wiring is designed to be as complicated and confusing as possible — making it no easy matter to snip the wires or re-route the circuit.
The most basic electronic immobilizers work by breaking the starter motor circuit. More sophisticated (and therefore more difficult to bypass) versions are connected to the ignition system. Some systems switch themselves on automatically whenever the car is left, which saves you having to remember. The device used to override the immobilizer varies from a key which you insert into a socket in the dashboard, or a remote control handset, or a key pad which you use to type in a secret code number.
It is possible to buy a combined alarm/immobilizer system which prevents the engine being started when the alarm is activated — this is the best system to go for, because an immobilizer by itself will not protect your cars from smash- and-grab thieves or vandals, or from being loaded on to another vehicle or towed away.
Check out which system is best for you with a dealer — don’t buy secondhand, because a manufacturer’s warranty is well worth having, and with a dealer you can find out exactly what features the system has and arrange for it to be professionally fitted. It can be very dangerous if an immobilizer activates when the car is moving, so ask your dealer what safeguards are built in to prevent this.
Most immobilizers are invisible, so remember to place the manufacturer’s stickers in the window to warn potential thieves that the car is protected.
For a top-of-the-range high-performance or luxury car (or caravan) thieves are prepared to put in a lot of effort. Organized gangs have equipped themselves with tow trucks so that they can transport stolen vehicles to a workshop where immobilizers and alarms can be deactivated out of the public gaze. Once the car is in their hands there is little hope of recovering it — unless you have it fitted with an electronic tracking system.
As soon as you report the car or caravan stolen, a high-powered transmitter will send a coded message to activate a small transponder unit concealed within your car, which then broadcasts a silent homing signal. These signals can be picked up by the police (there are control units throughout the country equipped with Tracker detectors, especially at ports and on major motorways). Even if the car is hidden away in a garage, the police can locate it.
Tracker systems are expensive, so it’s really only worth considering for a valuable car. Contact one of the major motoring organizations or your insurance company for further details (your insurance premiums may