...no brake lights...

Can anyone enlighten me to what my problem could be?
The problem is I have no brake lights, I have changed the bulbs, fuses, stop switch on the brake pedal, and checked the ground, I have also checked the wiring from the bulb itself to where it goes into the back seat. It has really thrown me for a loss to what it could be. Any information would be appreciated. Thanks

Do the turn signals work on the back? If the turn signals do not work, replace the turnsignal/multifunction switch.

I have turn signals in the back as well as tail lights, I am seriously hoping its not the wiring. Is there relay or something I can check?