No Brake Lights

2004 SES 24V Duratech with spoiler.  Parking and directionals work, but no brake light either side.  Eye level brake light in spoiler does come on.  Checked the fuse for "stop light" (fuse #17 if that's Ford's definition of brake lights) was OK.  I'm figuring brake light switch on the brake pedal, but as I said, the light on the spoiler works and I'd think it would run through the same switch as the tail brake lights.  Checked plugs and grounds both tight to each light.
 
Any ideas?
 
Thanks.

The 3rd brake light has another source for its current other than the stop light switch.  Check for current going to and out of switch.  If no current coming out, replace switch.

The problem ended up being the emergency 4 way flasher button was stuck half way out.

Thanks for the update..