one of my brake lights doesnt work. When my headlights/taillights are off it works fine when i brake. Once I turn my headlights and taillights on my passenger brake light does not light up when i press the brake. However it does stay lit with the other taillight continuously. Any ideas?

 

Sounds like a brake switch issue

http://www.agcoauto.com/content/news/p2_articleid/243

 

I'd think brake switch would affect both taillights. Sounds like a ground issue or stray current path on that side.