'98 Monte LS Brake light problems

I have no clue when it comes to electrical problems, and I'm pretty sure that is what I have. I have a 98 monte carlo and the brake lights have gone out. All of the other lights work, the running lights, blinkers, and the middle brake light in the rear window. (no problems with the headlights or anything) the brake lights quit working and it's not a fuse because I checked that and changed it just to be safe. The blubs are still working because the running lights and the blinkers work, (it's all one bulb) Does anyone have any input for me?

It could definately be the turn signal switch. Check that out.

Well it has been well over a year since this post but I haven't gotten a chance to reply.... long story first time back on this computer since then, anyway, you were right, it ended up being the turn signal switch inside the steering colomn, had to take it to the dealership to get it switched out, but it's been working fine since then.