Hello and thank you for trusting us with your question. I'm DJ.
First off, there's two fuses, one for the 4 way flashers and the other is for the turn signals. The one for the turn signals is 10 amp and is under the dash on the left side.
The flasher is the same for 4 way as turn signals, so that's not the problem.
Either the hazard switch or the turn signal switch could cause the problem.
So the first thing to do is check the fuse. Then for the next step you'll need to locate the wiring that goes to the combination switch (headlight and turn signal switch). There's three wires to locate.
Green with a blue stripe.
Blue with a red stripe.
Green with a yellow stripe.
Jumper either of the green wires to the blue wire with the key on. You can use a paper clip bent into a U shape or just a piece of wire.
Hooking the green-blue to the blue-red wire should cause the left turn signal to work.
Hooking the green-yellow to the blue-red should cause the right turn signal to work.
Let me know what happens when you do this test and we'll figure this out.