92lexus

Hello everyone,
I have a few questions concerning a flasher on a 92 ls400.
heres my problem- The right turn signal works fine, but when i try to use the left turn signal, i hear this screaching noise coming from the flasher, and i get no left turn signal at all.
Does this sound like a bad flasher, or possibly something worse?
Can I buy a new flasher from autozone, or must i go to the dealer, and how much do they usually cost?

Thanks everyone for the help,
Barry