All brake lights are out. I have checked all fuses, all the bulbs, and the brake switch at the master cylinder. There is no trailer wiring harness in the driver side back cubby and no appearent broken wires. All the driving lights and turn signals still work. What else can I check. Thanks in advanced for your help.

Have you checked the brake switch on the pedal? Not many Explorers have them go out, but it's worth looking into. Good luck with it.

I will give that switch a look later on today...thanks again.