can someone tell me which bulb do i need

one of the bulb do not light up anymore and i get yellow sign on my front dash panel

its the one that the most closest one to the GS400 sign to last 0 on the right (big light) i belive it works as breaks and as a day light.. not 100% sure though

 

If it's a brake/tail light then it's a 7443. If it's a tail light only then it's a 7440. The 43 is a double filament, and the 40 is a single filament. Any parts store should have replacements. Try these if you want a different aftermarket look.

http://www.tuneshops.com

and

Trend Cruiser

Hope this helps.