[12Ounce]

What ModMech is saying is that the key (and key tumbler) are not the "switch".
The switch is an electrical black box located under the dash. The switch is connected to the key tumbler thru a linkage rod. The switch sometimes needs some mounting screw adjustment to sync it with the tumbler.
The switch may need to be replaced. Mine was replaced at about 100k miles.... and it should have been replaced sooner.