ok, i dont know when this started, but i just noticed it about a week ago. the drivers side parking light/blinker/whatever, (the bulb in the actual headlight housing, not the running light bulb that is IN the front bumper)
it sometimes wont come on when i turn the headlights on.

sometimes it will turn on right away, sometimes it doesnt come on at all, and sometimes it will come on and then go out later as im driving. when i use the turn signal, it ALWAYS works(the same bulb). so i dont think any bulbs are blown, it seems to be a wiring issue. does anyone know how all that works, and what i could check to get that running light working properly again?

the other side works perfectly.

 

You need a new bulb.

What is happening is that the filament in the bulb is broken but sometimes when it gets hot and you go over a bump it attaches it self to the other side and it will work. That's why they say if your headlight were ever to go out to give it a few smacks and usually it comes back on. Its a temporary fix.