To be sure, you should:
* Consult your owner's manual: This is the best resource for the exact location in your specific vehicle.
* Look near the fuse box: This is the most common location for flasher units.
* Search online forums: Search for "1989 Chevy Cavalier flasher unit location" on automotive forums. Someone might have already posted a picture or detailed instructions.
Remember to disconnect the negative battery cable before working with any electrical components in your car to avoid accidental shorts or shocks.