* Under the driver's side of the dashboard near the fuse box. This is the most common location.
* Behind the kick panel on the driver's side. You might need to remove the kick panel to access it.
To be sure, you could:
* Consult your owner's manual: This is the best source for the exact location.
* Look for a small, usually square, black box with a button. This is the typical appearance of an inertia switch.
* Search online for a 1989 Oldsmobile Cutlass Ciera wiring diagram: These diagrams often show the location of the inertia switch.
Remember to disconnect the negative battery cable before working with any electrical components in your car.