My left one would come on for aprox 60 seconds then go out, I took it to the dealer and they replaced the bulb, so it sounds like yours is out, it is extreamly easy to just do it yourself if you can't get to the dealer.
Have the "balast" checked too. From experience with my Evo, Bosch had to replace it several times cause it died many times in the past. Do your lights vibrate when driving on rough roads? Mine does and i find that strange.
I thought it was my Ballast also since my IS F only had 2100 miles on it, but the dealer said sometimes you get a bad bulb. What I would do is take the buld out of the working side and try it in the side that dosen't work, if it works, problem solved, if it dosen't work, looks like a trip to the dealer!