turn signals not working

Hi, I have this problem, just a few days ago on my 88 tercel my front turn signals stopped working. I've noticed the left blinker on my instrument cluster blinks faster, as well as my rear left turn singal. Both the rear turn signals work.
I've replaced the bulbs for the front and it still is not working. I've checked all of the fuses and they are ok.
Can anyone give me any other ideas where to look?
Thanks

Check the grounds for the blinkers. Take them off and clean them if dirty. Are either of the turn signals dimmer than the other?