• The ignition switch turns your vehicle on. It provides the connection between the battery and the starter, and gets the vehicle going. The ignition switch sends a rush of electrical power to the starter when it is turned on, causing the car to start. By turning the engine's power supply off, it also prevents the vehicle from starting when not needed. The ignition switch usually has three possible options: on, off, and start. The ignition switch supplies and controls about 50 percent of your vehicle's total power needs. When an ignition switch has problems, there are several symptoms.
  
  

Vehicle Doesn't Start

• Since the ignition switch is what prompts the engine to start, the surest symptom of a problematic ignition switch is when the vehicle is unable to start. If the car either does not start at all, or takes several tries to start, it may be the symptom of a faulty or bad ignition switch. However, this could also be a symptom of other problems, such as a fading battery. If the vehicle sputters and tries to come on but fails, or comes on only partially, it is most likely the battery. If the vehicle simply doesn't start at all, it is most likely the ignition switch
  
  

Headlights and Dashboard Lights Go On

• If the headlights and dashboard lights go on but the vehicle doesn't start, this is another clear sign of a bad ignition switch. Since it is the battery and not the ignition switch that turns on the headlights, if the engine won't turn on but the headlights and dashboard lights will, your problem is most likely caused by an ignition switch.
  
  

Heating Up

• Another symptom of a bad ignition switch occurs when the switch gets short circuited and heats up. If the switch is impossible to touch with the hands, it is a sign that the ignition switch is facing a problem rooted in the vehicle's electrical and wiring system. The ignition switch is connected to a series of high-resistance wires. Any of the terminals connecting these can heat up. This results in arcing of the terminal(s), which further heats up to the extent that it melts the bakelite insulating base. From there, the wiring directly next to the ignition switch can heat up. When this happens, the vehicle jerks and doesn't start despite repeated turning of the switch.