The inhibitor switch from Ford is about $75, try www.rockauto.com and partstrain.com
The switch takes about .6 hours to replace.
To test the switch ,in both park and neutral the white/pink wire should have power from the ignition switch in the cranking position (get a friend to turn the ignition switch to starter position while you check for power). In both Neutral and Park the red/light blue should bring power down to the starter motor solenoid on top of the starter.
Ignition off, neutral safety switch disconnected in neutral and or park, the red/light blue wire and white/pink should have continuity.