Flashers work but turn signals will not 1989 bonneville

There are usually two flashers that are used on most cars. One for the turn signals and one for the hazard lights. They are usually located under the dash. If you don't know what they look like, then go to the parts store and ask to see a new one. Once you locate both of them, see if they have the same part number stamped on them. If they do, then switch them and see if the signals work.
REMEMBER : The key must be turned on for the turn signals to work in most cases. The hazard flashers will work with the key off.
If the signals work, then replace the turn signal flasher. I hope this information is helpful and thank you for using Fixya.com.