A cars ignition switch has multipurpose utility. As its name implies, the first and foremost function is to engage the ignition system of the car, or to start the car from a dead state. Secondly, it can provide access to various features or accessories of the car, like the stereo system, the radio, the windshield wiper, the headlights, brake oil levels, gasoline levels, dashboard backlight etc. The ignition switch can also be used to control the bonnet of a car.
While in some cars the electronic switch which actually switches on the rest on the system depending on the feedback from the ignition lock cylinder are integrated into a single unit, in other cars they can be separated from each other. Based on this variation, the term ignition switch can be used without a doubt for both the electronic switch and the ignition lock cylinder. The distinction is quite difficult to adjudge since both types of systems are found in abundance.
Even in the absence of ignition switches, cars did exist! The cars engines then used to be started or ignited by mechanically turning a crank, whose associated shaft used to turn the engine, moving it out of its inertia. In the present times, a flywheel associated with the cars engine is brought into action through an electric relay system activated by the ignition switch, ultimately starting up the engine. The flywheel is a large, flattened disc which has teeth on the outer circumference. A gear associated with the starter system engages the teeth of the flywheel when the ignition switch is turned ON, thus bringing the flywheel into life briefly with a huge momentum transfer, which starts up the engine.
The typical ignition system has four configurations, Off, Accessories, On, and Start. In some cars there are two dead states of the key, Off and Lock; OFF switches off the car, while the Lock configuration lets you remove the key from the ignition cylinders keyhole. In the accessories configuration, certain accessories as mentioned earlier that remain off in the OFF and LOCK configurations in order to prevent the car’s battery from being drained, use up very low power. People are often advised to use the Accessories position often for a longer car battery life.
Since features such as the indicator for fuel and brake oil levels are turned on only when the ignition switch is in the ON state, since they are useful when the car is running. Since the start position is meant only to jump start the car engine, the key is not allowed to remain in the start position for long, and is turned automatically to the ON position by spring action. When the switch changes its configuration from Start to ON, the starter system is cut off from battery power, and the cars engine starts running by a relay through the flywheel.