Turn signals won't work?

Hello,

It sounds like you might have an issue with the turn signal switch.
Unless you have already done, change your flasher relay out.
The flasher is located behind the instrument panel below the radio (see diagram below).
I think there might be a short in the multi function switch, which making the lights act strange.
You will have to trace the wires to see what has a short.

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

I have attached the wiring schematics for your reference.

Please let me know of any questions.

Thank you.