How Do You Hook up an RPM Gauge?

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An RPM gauge, also known as a tachometer, measures engine speed in revolutions per minute. Begin by selecting a location to place the tachometer, and install it using components that come with the kit. Drill a hole in the firewall where the tachometer wiring goes through to the engine compartment. Connect the wires from the tachometer to the appropriate wires on the vehicle.

  1. Gather the parts and tools

    Purchase a tachometer from an auto parts supply store or salvage yard. Gather necessary tools such as a sharp knife, wire cutters or strippers, ratchet or socket, screwdriver, drill, tie wraps and rubber grommets.

  2. Install the tachometer

    If a hole does not exist in the firewall, drill one where the wiring can go through into the engine compartment. Install a rubber grommet to prevent wire fraying. Mount the tachometer in a desired location using the parts that come with the tachometer.

  3. Connect the wiring

    Run the wires through the hole in the firewall and mount them to the firewall of the engine compartment as needed. Connect the black wire to the engine’s grounding connection. Connect the green wire to the electronic coil negative post. Connect the white wire to the dash lighting. Connect the red wire to the ignition switch.

  4. Test the tachometer

    Start the vehicle and ensure that the tachometer is working; use electronic testing tools or take the vehicle for a test drive.