G'day Mate and welcome to TBN from Downunder.
If the blinkers (four way flashers) work but the turn signals don't then there is nothing wrong with the 'bulbs', flasher relay or capacitor circuit... that is off of your 'light switch'. The problem lies with the Left/Right turn signal switch or switch circuit. If both Left/Right indicators do not work then look for something common ie: a fuse or a loose wire.
Your local JD Dealership (Parts Dept) should be able to provide you, free of charge, a wiring diagram. (I know that my Dealership would do this)
Enjoy the site.