Replacing tail/brake/turn/backup lamp bulbs 1. Turn the headlamp switch to OFF and open the tailgate. 2. Remove the two bolts from the lamp assembly. 3. Remove the lamp assembly. 4. Rotate the bulb socket counterclockwise and remove it from the lamp assembly. 5. Pull the bulb straight out of the socket. Reverse steps to reinstall bulb(s).
This is straight from the owners manual. If you don't have an Owners Manual you can get one here free: http://www.autousermanual.com/view/ford/explorer/2007/sport-trac/