2000 Ford F-150 Brake lights

The brake lights on my truck have quit working, it started as an intermittant problem, now they do not work at all. The fuses are good, the brake light switch has been changed. The cyclops light on the cab works fine and always has.
Inspection of the wiring harness from the engine compartment back to the brake lights has revealed no indication of a broken wire or a short.
I do most all my own repairs and such but this one has me scratching my head.