So I've been having this problem where my left side low beam stops working for a while, then it comes back randomly. It happened in December, it cut out for 3 days and then came back, I haven't had the issue since, now it's doing it again. I know it's not the bulb, is it possible that the ballast is acting up or is it just a loose connection?

 

Have you tried inspecting it? The headlight is easy enough to remove

 

That's probably exactly what it is. I say start poking around the headlight until you can replicate the problem, doesn't sound too complex.

Try swapping the ballasts to see if the problem persists on the same side. That way you'll know if its the ballast or the wiring.