[chasealley]

Do you notice any difference in the action of the lights switch? It may be possible it is worn in the 'off' to 'park lights' positions.

I'm just guessing because I'm not sure how the system works. We have a remote start system (installed before we got it) and when it kicks in the park lights go on automatically. Kind of annoying because the Ford manual says installation of a remote starter can cause the anti-theft to become inoperative. So obviously there is more going on with the park light system than just a switch.

May be worth taking it to Ford and letting them put it on the scan tool to check for chassis or electrical faults.