How Does Hot-Wiring a Car Start the Engine?

Bypass the Car's Ignition Lock

Hot-wiring a car enables a car to be started by bypassing the car's ignition lock on the steering wheel column. Normally, a key has to be inserted into the ignition lock and the key turned in order to start the chain of events that lead to a car being started. Hot-wiring eliminates the need for a key.

Creating Necessary Spark

Hot-wiring manually produces the necessary spark to cause the engine to turn over, or start. Normally, the car battery is what supplies the spark, or electricity, that ignites the air/fuel mixture inside the engine, which in turn causes the process of combustion, or a running engine. Hot-wiring a car, which entails the severing and then splicing of two hot ignition wires, creates the spark that eventually travels to the end of the spark plugs and ignites the engine.

Constant Contact

The hot-wired car will run as long as the two ends of the spliced ignition wires remain in contact with one another. With the absence of an actual ignition key, the spliced ignition wires serve as an artificial ignition key; when the wires are removed, it is the equivalent of turning off the ignition key.