HomeTips & GuidesHow to Wire a Tachometer: General Steps for Wiring a Tach

How to Wire a Tachometer: General Steps for Wiring a Tach

Welcome to our coverage on how to wire a tachometer and the roles of this device in your car. 

Most of the car’s repairs are doable without requiring the hand of a professional mechanic. 

Among the installations you should know is the wiring procedure for a tachometer. 

But before delving into the wiring details, what is the fundamental role of this component? 

So, for more on this and everything you’d like to know about tachometers, check out our guide. 

Table of Contents

What Is A Tachometer?

It is a gauge responsible for measuring and providing a car’s engine speed. 

The device provides the speed details in revolutions per minute, popularly abbreviated as RPMs. But why is the device so crucial in a car? 

  • Its display helps you understand and track the car’s engine performance. 
  • It is essential when setting up your car’s idle speed and rev limit. 
  • You can also tell the car’s maximum revolutions per minute limit or when you’re closing the revolutions redline. 
  • It also helps you determine the engine revs when the car travels at certain speeds. 

Tachometer Working Principle

The device works with other engine components, such as the ignition coils’ negative terminal, engine computer, or an ignition control box. 

It receives an electrical pulse signal from either of these devices and converts it to a mechanical signal or a digital display.

The final display in modern vehicles is in digital form. 

Which Tachometer Should I Buy?

A Speedometer and Tachometer. 

A Speedometer and Tachometer. 

You’d be forgiven for wondering which is the best tachometer for your car, as there are far too many types in the market. 

They are available in various colors and sizes, but the most important consideration should be the compatibility with your engine cylinders

Note that there’s another crucial role of the tach from those we’ve highlighted above. 

The device, especially in modern cars, features a shift light. This display activates after your car attains a particularly set RPM. 

It is critical to inform the driver of the ideal shift time without necessarily checking out the tachometer. 

Finally, there’s also the RPM recall feature on the tachometer, which indicates the highest reached RPM before a reset. 

How To Install A Tachometer

Below is a detailed explanation of the steps required when installing a tach. 

Assemble the Tools and Necessary Components

You will need the following parts: 

  • A Tachometer- Ideally, it should match the number of cylinders in your car’s engine. 
  • Tachometer Wiring Harness – There are many wire harness types. Ensure you purchase one that best suits the cables you’ll be using. 
  • Mounting Bracket – Purchase a mounting bracket that matches your tach size. 

Pick an Ideal Mounting Location

A Tachometer RPM gauge. 

A Tachometer RPM gauge. 

Select the ideal place on your car to install the tach. The tach location could be on the steering column, dashboard, directly on the hood, or even the instrument cluster

Whether you’d like to install the tach below or above, no problem, as the device has a provision for either of the options.

 It has a pedestal featuring screws/bolts that allow an above or below attachment. 

There are even tach models that allow use with a clamp, allowing for attachment onto the steering column. 

This location, especially between the instrument panel and the steering wheel, is excellent as it allows great visibility while driving. 

The most important consideration when picking a location is to ensure the tach is easily visible and doesn’t obstruct other display components. 

Prepare the Mounting Surface

You don’t want to mount the tach on a surface that’s dirty and has grease or dust/debris, as it’ll be hard to clean the part after installation. 

So, ideally, you should clean the surface thoroughly before the installation.

After cleaning, mark out the parts where you’ll drill in the installation holes. 

The tach’s has a template that will help you in the markings. Next, install the mounting bracket if your tachometer requires it for installation. 

Ensure it is securely fastened onto the dashboard/installation surface with the provided screws. 

If in doubt about any step, refer to the manufacturer’s instructions. 

Install the Wiring

Car wires. 

Car wires. 

The tach’s user manual and the vehicle’s wiring diagram will be useful during this phase. 

Refer to them on the appropriate wiring procedure. You’ll also need to identify the key parts of the installation, such as the ignition coil.

 It is the part where you should install the tach. 

Once you have connected the cables as per the user manual’s instructions, insert the tachometer signal wire onto the harness. 

Ensure you’ve created a secure connection. 

You must also install the tachometer’s power wire to an appropriate power source.

 Most importantly, fix a fuse between the tachometer and the power source as a safety precaution. 

Also, install the tach’s grounding wire to an appropriate area on the vehicle’s chassis for grounding. 

Route the Wiring

Electric Wire Zip Ties.

Electric Wire Zip Ties.

This step is significant if you installed the tach above the dashboard and the installing wires are dangling all over. 

Route and secure them with a zip tie or any other appropriate technique to ensure they don’t move, especially while you’re driving. 

When left all over, the cables are also likely to interfere with the driver’s view when driving. So, this process is fundamental. 

Test the Tachometer

Once you’re done, ignite the vehicle to confirm if the tach is working appropriately. 

You can easily tell if there’s a problem with the device by checking out the RPM readings as you rev the car’s engine. 

Is the tach providing accurate RPM readings? 

If everything is running appropriately, you can embark on the next step, which involves double-checking to confirm every connection is okay. 

Also, turn the tachometer to ensure you get a perfect viewing angle when driving. 

Finally, clean up the surface by removing all the trims that resulted from the installation. 

Test Drive

It’s time to do a test drive and check how the tach displays when exposed to various driving conditions.

 A properly working tach (with accurate readings) should display RPM readings that align with the vehicle’s engine performance/RPM range. 

What Type Of Tachometer Wiring Connection Should Be Used?

Installing an additional wire via Heat Shrink Tubing. 

Installing an additional wire via Heat Shrink Tubing. 

How do you complete the wiring connections, especially when dealing with wires that are shorter than required? 

There are many ways to do it, depending on the gauge wire connection. 

For instance, you can opt for heat shrink tubing for installations that allow soldered connections. 

But for tach signal wires that don’t allow soldering, a butt connection will come in handy. 

How about a setup whereby you expect to remove the tachometer frequently? In such a case, a quick-release connection will do the job. 

The bottom line is that the connection choice depends on the case you have at hand. 


Install a tachometer to your car with the above-provided steps. Note that what we have covered are the general installation steps, so that they may vary from one tach model to the other. 

Therefore, it’s essential to use the manufacturer’s manual in tandem with these instructions. But you can do all these installations without the help of a mechanic if you understand basic car wiring principles. 

Hi I am Christa, sales manager of Cloom.

I have extensive expertise and experience in wiring harnesses and I believe I can help you.

And we have a very professional technical team who can clearly understand the customer’s needs and give professional suggestions and solutions after receiving the drawings.

If you also have wiring harness needs, please send me the drawing so that we can give you our quote and start our business.

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