Well it's in the steering column and it's not too difficult to get to, you don't need to drop the whole column . If the problem is as I expect you will see a darkened brown burnt terminal and or a burnt wire.
If it is what I suspect you may get it to work for a while by just installing a new switch but eventually it will fail again and probably not when your at or near home. Putting in the relay to handle the current and use the switch to control it is a better more perminate fix.
You could also down load the wiring diagram from the Internet. (Look. Under workhorse chassis manual, the wiring digrams are in the back.)And use a test light to verify the output to and from the switch.
Also Chech out
http://www.oemys-performance.com/ , look under dyi projects ignition switch fix.
Good luck.