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[2024 Updated] How To Test a Starter Relay

Are you wondering how to test a starter relay? Are you fixing car issues but don’t have the experience or knowledge to pinpoint what is causing your car to not start up? Testing a starter relay doesn’t require advanced knowledge of automobile mechanics, so if this is the issue with your car, then tackling it yourself can save on expensive repair costs.

This blog post will take you step-by-step through the process of testing your starter relay and provide tips. Let’s jump right in and learn how to effectively diagnose an automotive problem!


How does Starter Relay work

The moment you twist the ignition key, a fascinating chain of events unfolds to bring your car’s engine to life. At the heart of this process, the starter relay leaps into action, transmitting a subtle electrical impulse to the starter solenoid.

In response, the solenoid amasses a surge of mighty current straight from the vehicle’s battery, awakening the solenoid and propelling it to dispatch power to the starter motor.

As the motor engages, the flywheel’s rotation sets the stage for a smoothly running engine, and it’s all thanks to the tireless teamwork between the starter relay, solenoid, and motor.

This incredible sequence, present in all modern starters, serves as a testament to the intricate synergy between automotive components that, in tandem, power our journeys every day.


Bad Starter Relay Symptoms

Imagine hopping into your vehicle, excitement coursing through your veins as you eagerly turn the ignition key, only to be met with a resounding silence. Instead of the mighty roar of the engine, you hear multiple clicks, the starter relay persisting even after the key has been turned off.

Frustration sets in as you find yourself struggling with intermittent starts, occasionally having to turn the key on and off just to get the engine running. This bewildering conundrum could be due to a faulty starter relay or worn-out connections that hinder the necessary current from reaching the coil in the starter relay. Or perhaps, it’s time to bid farewell to that failing battery that’s no longer capable of providing sufficient power.

Whatever the cause may be, it is crucial to conduct a thorough series of tests on the starter relay circuitry to get to the root of the problem and reclaim the harmony between you and your trusty vehicle.


How to test a starter relay

Before you begin testing your car’s starter relay, you will need to gather a few materials.

Materials You Will Need

  • A digital multimeter
  • Wire

Additionally, having a friend or family member available to turn the ignition while you perform your assessments can be incredibly helpful to ensure accuracy and ease throughout the process.

Before diving into any testing procedures, it’s crucial to first ensure you have a properly functioning battery that’s fully charged. If in doubt, testing the available battery to confirm it’s holding a 12V charge can help rule out any issues arising from the battery itself.

How-To-Test-a-Starter-Relay 1
How-To-Test-a-Starter-Relay 1

Related: How To Reset Anti Theft System Ford F150?

Now that your car is prepped, locate the starter relay you’re investigating, which should be positioned close to the battery with the positive terminal wire attached. To aid you in your evaluation, ask a friend to switch on the ignition while you attentively listen for the sound emanating from the starter relay.

If you hear one or more faint clicks, proceed to check the relay for electrical resistance. However, if there’s a single, assertive click, you’ll need to examine the starter relay for voltage drop instead.


Step 1: Test for Electrical Resistance

All you have to do is place the probes of your handy multimeter on both the ground lead and ignition circuit terminal. If you get a reading higher than 5 Ohms, then bingo – you’ve got a starter relay in need of replacement.

However, if you’re still unsure about the result, you can also try using a wire jumper for checking resistance. Simply connect the wire between the ignition circuit lead and the battery lead and listen for a strong click. If you hear a weak click, that’s another indicator of a faulty starter relay.

Lastly, don’t forget the good old method of checking resistance with your multimeter. Place the red probe on the ignition circuit terminal and the other probe on the ground terminal. If the voltage doesn’t read 12V when the ignition switch is turned on, yet again, you’ve found a telltale sign of a malfunctioning starter relay.

Step 2: Test for Voltage

Setting your multimeter to 20V DC will help you determine whether the starter relay is the cause of your troubles. Place the red probe on the connection of the red wire from the battery and place the other probe on the connection leading to the ignition switch circuit – typically, a black and thin wire.

Once that is done, have your helper turn on the ignition as you read off your multimeter. Ideally, it should be no more than 0.2V; anything higher would indicate that there’s possibly a problem with electrical conductivity in which case, you will need to inspect and clean out those leads first before coming to any conclusions.

If even after cleaning them out it doesn’t seem to improve then it may be time to replace that starter relay with a brand-new one.

Related: How To Reset Mass Air Flow Sensor?

FAQs about How To Test a Starter Relay

Where is the starter relay?

It can be either under the hood, behind the fuse box or hard-to-find on the right fender of the car. Having gone through this dilemma myself many times, I know what you must do – open up the upper dashboard fuse panel and look for a black, cylindrical relay closed with mounting posts and leads. I suggest double-checking its location as not all cars have their starter relays installed in the same place which leaves some of us searching for longer than necessary!

Can you fix the starting relay?

If you find the starter relay on your engine is not functioning, there’s no way to repair it – you’ll have to invest in a new one.

Is it easy to replace the starting relay?

With the proper tools and wiring knowledge, this process can be completed quickly. By simply unplugging the old relay and connecting its replacement in a fuse box setup, you’ll have that car running smoothly again.

What is the cost of starting relay replacement?

The total cost may range from just $65 to a max of $72. Estimates for labor are typically between thirty dollars and thirty-seven, with parts an additional cost running between thirty-five bucks up to forty-five.

How long does the starting relay last?

Normally, this small yet essential part should last you well over 100 miles, a testament to its durability and minimal wear-and-tear nature, thanks to its few moving parts. Although the starting relay is built to last, you should still be aware that contact burnout poses the greatest threat to its life.

Is the starting relay the same as the starting solenoid?

While the starting relay and starting solenoid terms may be used interchangeably, they each serve a specific function in modern cars. The starter solenoid is not only responsible for engaging the starter motor, but it also plays a crucial role in moving the starter pinion into engagement with the engine’s ring gear.

On the other hand, the starter relay, which might be called the “starter solenoid” in some cars, primarily supplies power to the actual starter solenoid. Although both components are essential in the car’s starting process, they distinctly contribute to the overall functionality, making them quite different from one another.



We hope this guide has been helpful in helping you diagnose and repair any starting problems your car may be suffering from. Knowing how to test a starter relay can certainly make life easier when it comes to troubleshooting, as well as save you time and money that would have gone towards taking the car into a garage. With perseverance, some basic tools, and our tips here, we’re sure you’ll be able to get your car running smoothly again in no time. Good luck!

Timothy Ballard

I’m Timothy Ballard, owner of a used car dealership in Springfield. I love just about everything automotive, but I have a special place in my heart for trucks. I’m an ASE Certified Master Technician, so I know my way around a car. In my spare time, I enjoy traveling with my family and hiking new trails.

1 thought on “[2024 Updated] How To Test a Starter Relay”

  1. When attempting to start your vehicle, you may typically hear the click of the starter relay. However, if the starter fails to engage despite hearing the relay click, it doesn’t automatically indicate a faulty starter. Several factors could contribute to this issue, such as a low battery, poor connections between the battery and starter, or between the starter and battery. Once you’ve examined the connections, the next component to consider is the starter itself.


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