Open the hood of your vehicle and locate the engine bay.
Locate the distributor. It's a cylindrical part located near the front of the engine that has a wire harness connected to it.
Look for the tachometer signal wire connector near the distributor. It may be a single wire or part of a multi-connector.
The tachometer signal wire on a 1989 Honda Civic hatch is typically a thin black or white wire labeled "TACH" or "RPM."
Use a multimeter or a test light to confirm that the wire you have identified is the tachometer signal wire. With the ignition key in the "ON" position, the multimeter should display a fluctuating voltage reading or the test light should illuminate when connected to the tachometer signal wire.
If you are having difficulty locating or identifying the tachometer signal wire, you may need to consult a wiring diagram or seek assistance from a qualified mechanic.
