Of course check your plugged connections, is your switch bad? Open it up and look for corrosion or obvious damage.
With the wiring problems you've had with that bike sounds like you may just have a F'd up harness man. If you're not concerned with high/lo beam you just want both on at the same time I guess you could just run a jumper wire over from the side that is getting power to the side that's not but that a half assed job lol.
If it were mine, and you haven't fixed the blinker issue you were having I'd go ahead and pull the harness out and have a good look over it for cuts slices and hacks and either repair or replace it. I had a brake light issue I just coulnd't find were the problem was I spent hours and hours trying to find it. Spent 40 bucks on a uncut Ebay harness and Viola fixed! Wish I could be more help I'm not that great with electrical stuff.