unless you have LED's make sure you get the conventional blinker fluid. if you get the new synthetic which is specially blended for use with LED's you will cut your filament life to minutes instead of years. don't say you weren't warned.
Sounds like you have something mis-wired in your headlight area, if you have a schematic of the bike (in your bike manual) the tracking of the problem will be pretty easy. I suspect you don't have a manual for your bike. For most bikes - all the wiring comes together in the headlight shell. Remove your headlight and track down where the blinker wires are connected to. You didn't mention if the winker not working is both on the left side or front or back.
The other item you could check for is a short of the left winker wire - but it's sounding like it's a mis-wire of the left winkers. If you don't have a manual for your bike, some manuals are available online for free - let us know what type of bike (and year) you have and may be someone here can point you to a manual.
Don't get to put-off, the guys here are just having a little fun at your expense, we only bark, we don't bite...