J and K AUTOMOTIVE TOWING AND REPAIR 1/12/2011The ignition switch in a vehicle is responsible for sending a signal to the starter motor so that the engine will start. While the switch has no scheduled service life, in most vehicles it lasts quite a long time. If the switch fails, however, you won't be able to start your vehicle. But before replacing it, check to see if the ignition switch is in fact faulty.
Open the hood and set the dial on your voltmeter to "volts."
Touch the red lead of the voltmeter to the power terminal on the battery.
Touch the black lead on the voltmeter to the negative terminal on the battery.
Check the voltage output. The output should be 12.6 volts. If it is less than this, the battery is discharged. If the voltmeter reads anything below 12.3 volts, it is completely dead and needs to be replaced.
Pull down the fuse panel cover inside the cabin of your vehicle. Remove the fuse for the starter with the supplied fuse puller (in the fuse box). Check the metal strip inside the fuse to make sure it is not burnt or broken. If it is, replace the fuse with another fuse of the same amperage.
Once you've determined that the fuses are good, insert the key into the ignition and turn the key. If the vehicle won't start and you don't hear a "click" when you turn the ignition to the crank position, the ignition switch has failed and needs to be replaced.