Got a stupid question? What is the purpose of the little bulb just left of the turn signal in this image? Mine seem to work sometimes but not all the time.

If I need to replace it, what should I be looking for?

Thanks Again

 

i do not know it's purpose, but i put it on with the fog light when it's a bit cloudy or it's not too dark to put the headlights on

 

Mine seem to come on with the regular lights, not with the fog lights.

Fixed them though. I found both wires loose on both sides. I must have pulled on them when I changed the turn signal bulbs.