Ignition switch problem

My 2001 F 100 tx ignition switch is bad I think? Motor starts great but the only way to turn it off engine is with the kill switch. I have looked at the diagram and the picture looks like the switch is not part of the harness. In the 2005 model the switch looks as if is part of the harness. Can any one tell me if they are the same part or if they are interchangeable.
More info, the gages do power down when the key is turned to the off position, the motor doesn't shut down.

[boats.net]

Yes the key switch is replaceable just plugs into main harness. Most of the time it's a bad main harness not key switch.