TSB for Brake lights?

I have been having a problem with the drivers side brake light not working, I thought that this was becasue my wheel cylinders were leaking causing brake fluif build up and the light not comming on (well this is the second thing the dear told me, the first was becasue my front brake pads needed replaced) so i go the leak fixed and also another bulb put, well today i was told that its not working again, so what could be the cause of this? I am taking it to another dealer so we will see how this goes.