The ignition switch is fed power through a series of fusible links. Fusible links are wires that are made to fail if too much current flows through them. THIS POST
has the related diagrams.
You can test the circuit with an Ohm meter as suggested. When the switch is in the positions noted on the wiring diagrams, you should see near zero ohms across the related pins which would indicate a good connection across the contacts inside the ignition switch. You will be testing at the large connector located under the steering column accessible by pulling the hush panel and knee bolster.
Do you have any codes present that may help limit the possibilities for the cause of your concern? Maybe you could list what is going on so we can actually diagnose that problem...?