Oldsmobile/Buick Repair: 200 buick century blinker, left blinker, side marker

Question
My left blinker does not work.  The front left blinker will blink fast, but not in the rear.  I have tried replacing the bulbs in the rear, and it doesn't work.  I contemplated replacing the flasher but wouldn't all the blinkers be out?  The right blinkers are fine.  is there more than one flasher for the blinkers? Any suggestions for me?

Answer
Only one flasher for the blinkers. There is another for the emergency flashers. I am curious how they are working.
I think you have a shorted bulb on that side, and it could be a front side marker bulb if you have those on that car. That would make the good bulbs blink real fast, cause it would be loading and tripping the flasher.
If the rear bulb doesn't work at all, the wire going to it may be rubbed through and touching metal.
Have you checked the rear bulb socket with a test light?

Van