Symptoms of a bad ignition switch include failure of the engine to turn over when the key is turned to the "start" position and failure of the radio or headlights to work when the key is in the "on" position. They also include a car that stalls out frequently when idling and an ignition switch that is very hot to the touch.
A test for a bad ignition switch is to turn the ignition to the "on" position but not all the way to start. If the dashboard lights, including the oil, brake, charge and other warning lights, do not come on, a bad ignition switch is probably at fault. Sometimes accessories, such as the radio, windshield wipers or power windows remain functional when the ignition switch is faulty but the car does not turn on.
When an ignition switch is beginning to fail, the car often needs to turn over several times before starting. Ignition switches can be tested with a multimeter. When an ignition switch goes bad, it cannot be repaired and must be replaced. Ignition switches often fail due to shorts in vehicle electrical systems; if this is the case, attempting to replace the switch must be done carefully due to the potential damage from the electrical current.