Starter/Neutral Switch

I'm having starting issues that began when I replaced the bushing on the gear selection lever. Frequently it will not start in Park and will when moved to Neutral. Sometimes the solenoid clicks a few times before it catches. The starter is less than a year old so is probably not the problem.

Where is the Neutral/Starter Switch located and how difficult is it to change? Any one know the part number for my 2000 Powerstroke?

Thanks for any help.