It's the switch I'd bet.
Because it points up, at the top of the column, it collects dirt and that grit prevents the contacts from closing. You can either replace it or try to clean it. I took mine apart (it was causing the turn relay to intermittently "buzz", it drove me crazy
) and cleaned it a few years ago, it's worked great since then.
It's kinda tricky to take apart (lots of plastic clips & springs) but if you're good at that kinds of stuff - go for it! As a test, maybe spray some WD into it and work it on/off a few times to see it if makes it better...