Since car thieves are constantly at work honing their craft, it pays to install a security system that's sophisticated enough to be an effective deterrent. If a car alarm is easy to disengage, and a thief has the expertise to disengage it, the security system loses its effectiveness.
Some security systems come with engine cutoffs, fuel-line cutoffs and other immobilizing features.
One of the simplest and most effective upgrades for a security system is to install a hidden switch that only the owner of the vehicle is aware of. A vehicle may be wired so that, for instance, it will start only if the radio is turned on before the ignition. In this demonstration, we install a system so that the car's engine can only turn over if the left turn signal is engaged before the driver turns the key in the ignition. Our example vehicle for this demonstration is a Chevy Cavalier. As in all automotive projects that involve electrical wiring, to avoid vehicle damage or injury, disconnect the vehicle's negative battery cable before you begin.