Left headlamp not working (can't find a solution so far)

I see a lot of posts about the headlamps not working. I am not necessarily ignorant when it comes to electrical work. Just bought a new bulb check the fuses everything appears to be fine yet the left headlamp does not activate.

In the past I have been able to tap the casing and it would pop on but that no longer works either.

I suspect that it is a connection issue. I read that the ballist could potentionally but I don't really know where to start there.

Anyone have any good tutorials on diy wiring or a fix for this problem. Sounds pretty common.