None Visible, I hear spraying WD40 corrects many.
Is it in the Jamb activated by the arm? Or in door panel? No Contact Points, and No Pin switches?

Located inside the door right under the latch. WD-40 works, but not for long. Best bet is to remove trim panel and lubricate mechanism with spray lithium grease.

See this post:

Ford door switches don't work (http://www.ricksfreeautorepairadvice.com/repair-topics/body-paint/ford-door-switches%E2%80%94a-known-problem)

The problem is on a friend of mines truck, With the door open, I manualy pushed the latch to the closed position, dome light went out, tried with ignition on as mentioned in your site, and each door chimes as supposed to, won't chime if switch has failed. Next time it fails, Will be easy to determine, Thanks again:
http://www.ricksfreeautorepairadvice.com/

Part of the latch assembly inside the door. About a $25 part and maybe 30 min to change if your mechanically inclined

Its been working fine, when it fails, I will open open door panel and check out. Haven't seen any screws, must mostly pop off clips. I see a couple plastic pieces that may reveal screws. Any know locations for the Explorer?