Only left front turn signal not working

Hello, I'm Danny.

It sounds like you are having a wiring issue. You will need to check for a bad, loose, corroded , melted, or otherwise defective connection. I would also check to see if you are having a good ground connection. Here is a tutorial showing how to check wiring:

https://www.2carpros.com/articles/how-to-check-wiring

I've attached a exterior lighting wiring diagram for your vehicle below. I've cut the picture into 2 pieces so you can view larger. Hope this helps and let me know if you have any further questions on this issue. Thanks for using 2CarPros.