How to hook up a tachometer

Updated July 20, 2017

A tachometer, or RPM gauge, tells you your engine RPMs and can be mounted on or near your steering column. A new tachometer will have specific instructions for its type of tachometer, but the installation of most tachometers will adhere to a few basic rules.

Determine where you want to mount the tachometer inside your vehicle. Most tachometers come with a mounting device to attach to the steering column.

Run the wiring from the tachometer into the engine compartment.

On the tachometer will be a black ground wire, a red wire and a green wire. Ground the black ground wire to the battery.

Locate your car's ignition coil. The ignition coil will be located in different places on different cars; consult your owner's manual.

Hook the red wire to the positive side of the ignition coil.

Hook the green wire to the negative side of the ignition coil.

If your tachometer has a fourth wire, it is for a light and can be hooked into your car's lighting system by splicing it into the wires that go into the dash. This is where you would use the wire strippers and electrical tape.


Different vehicles may require different wiring setups. When you buy a new tachometer, it will have instructions for your specific application.


If you don't hook up a tachometer correctly, it could burn up, melt or blow fuses.

Things You'll Need

  • Tachometer
  • Wire strippers (optional)
  • Electrical tape (optional)
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About the Author

Erin Stewart is a professional editor and copywriter who has served as a newspaper reporter, designer, and news editor, and currently works as part of a dynamic marketing communications team. Erin has a Bachelor of Arts degree in English with an editing minor from Brigham Young University in Provo, Utah.