Vehicle Security

Your vehicle is probably your second most expensive possession; you may well regard it as indispensable, but it is rarely given proper protection from the thief. Probably no more than one car in 100 is fitted with an anti-theft device other than the standard steering locks fitted by the manufacturer.

Police figures show vehicle theft is increasingly high; although roughly 80 percent are eventually recovered, most are badly damaged or vandalized in attempts to remove radios, tape players and accessories. In fact, having a vehicle stolen can add up to a considerable financial loss — depending upon the type of insurance you have — in terms of hire charges, replacement costs and loss of no claims bonus.

The obvious vehicle security tips are: fit an alarm to the vehicle; always lock it up; put valuables into the boot and lock it; retract the radio aerial; and lock the vehicle even when it is garaged.

Anti-theft devices

There are several anti-theft devices, available from motor accessory shops, which you can fit yourself. The simplest device is probably a lockable bar which fits between the steering wheel and clutch or brake pedal; this is fitted when the vehicle is left unattended. The bar will not provide a very high level of security, but should deter opportunist car thieves. Steering wheel devices, which can be fitted easily, greatly restrict steering wheel movement and prevent the vehicle being driven. You can remove the rotor arm from the vehicle’s distributor; this will prevent the vehicle being driven away — unless the thief happens to have an identical rotor arm. Locks Some insurance companies may insist heavy duty mortise locks, with deadlocking function, are fitted in addition to standard locks if the contents of the vehicle are above average value. The fitting of mortise locks to vehicles is best left to experts. You can buy bonnet locks for particular vehicle models; these can be fitted in addition to existing locks. Wheels Wheels are expensive and can be easily removed; protect them by fitting locking nuts on each wheel hub. One manufacturer supplies a set of wheel lock nuts which can be removed only with a special key.


Petrol cap

Lockable petrol caps, available from motor accessory shops, will prevent petrol syphoning and, because they are of better quality than ordinary caps, they will stay on the car should it overturn in an accident and prevent petrol leakage. Etching kit A useful deterrent against vehicle theft by professionals is to etch the vehicle’s registration number onto an area of its glass. Special kits are available for this purpose. Another possible visual deterrent is to buy an adhesive label with a car alarm motif.

Brake lock

This is one security device which is almost impossible to overcome. The device causes the brakes of the vehicle to lock on permanently when first used by a thief. However, you must remember to switch off the device before driving the car. This device is best fitted professionally. Padlock and chain Use a padlock and security chain with welded links to secure small vehicles such as motor cycles and bicycles. You can also use them to secure accessories to the vehicle.

Vehicle alarms

There is a wide range of vehicle alarms offering different degrees of protection; some are supplied with detailed fitting instructions which you should follow carefully. Manufacturers and agents will give advice on installation and help you choose a suitable model. Most alarms set off either their own siren or the vehicle’s horn when a door, boot or bonnet is opened. Those which activate the horn must produce a pulsed output because a continuous output, even for a short period, is likely to burn out the horn’s coil.

Security switch

Many vehicle alarms incorporate a switch in addition to the existing ignition switch to ensure the ignition remains turned off during the period the vehicle is left. The easiest and cheapest method of preventing a vehicle being driven is to fit a switch concealed inside the vehicle; most single pole switches will suffice, although one manufacturer supplies switches with suitable mounting brackets. Connect the switch in series with one of the leads to the ignition switch.


Ignition immobilization switches and vehicle alarms which incorporate these circuits may damage transistorized electronic ignition circuits. If your vehicle has electronic ignition, you should check with the vehicle’s instruction manual.

Specialist alarms

There are several alarm systems which are not suitable for DIY installation; some incorporate functions of alarm kits as well as making the vehicle lights flash on and off.

Pendulum alarm

One vehicle alarm in kit form consists of a pendulum mechanism which activates the alarm when the vehicle is moved or disturbed. This kit, which is low-priced and easily fitted, includes an ignition immobilizing function; but you have to adjust it carefully for sensitivity. The unit is prone to false alarms if the vehicle is moved accidentally or rocked by high winds.

Siren alarm

Another alarm kit is supplied with a siren and the necessary switches and cable; the switches are connected in series in a closed circuit. Fit the switches to doors, bonnet and boot lids; the on/off switch is fitted outside the vehicle and immobilizes the ignition. When activated, the siren sounds for 30 seconds and resets itself provided the entry point has been closed; if it has not, the alarm will reactivate and continue to warn of intrusion. Ultrasonic alarm A recent development is a device which fills the interior of the vehicle with sound waves; any change in the wave pattern activates a loud hi-lo sounder. Installation is very easy and the device gives protection even if only glass is broken in an attempt to gain entry. The unit offers good protection for caravans and cabin boats and its ultrasonic beam can be adjusted from 2-4 m (or 6-15ft). The sounder cuts out after about 50 seconds and resets. The unit can be supplied with a pulsed output to operate a vehicle horn and a closed circuit function can be included so the alarm operates via switches on the boot and bonnet. Electronic alarm One alarm kit, which is supplied with fitting components, is literally a ‘box of electronic tricks’. The unit automatically switches itself on when the ignition key is removed; when activated, the vehicle side lights flash and the horn sounds. There is a delay in the system connected to the ignition so the driver can deactivate the alarm as he puts the key into the ignition. The system has the disadvantage that valuables left in the vehicle could be stolen before the alarm sounds, but it is otherwise difficult to overcome.

Sensor alarm

Another vehicle alarm has sensors which react to high frequency vibrations such as those produced by knocks or tampering with doors. An alarm cut-off is incorporated and the sensors are unaffected by high winds or traffic vibrations. The same manufacturer provides a sensor system for installation on motor cycles. The systems may require professional installation for best results.

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