No Brake Lights

I have a 99 silverado ex cab and i recently encountered a problem, i have no brake lights but the bulbs, fuses relays and brake switch seems to be working fine. has anyone had this prob and can give me an idea where to check?

i would check under the rear of the truck next to the spare tire where all the wires plug into a junction block .... thats where the right side tail light the leftside tail light and the trailer connector plugs in .... there should also be a plug coming from the front with all the power for these different things

I'll check that out thanks.

my 99 silverado had the same problem...In my case it was the junction box that connects all 3 wires as was stated above....I finally came to this conclusion after using a light probe and turning on the 4 ways....and this junction box had an open in it.....hope this helps....