4 Symptoms of a Bad Starter Relay (& Replacement Cost)

The starter relay controls the power output to the starter solenoid. Here's how to tell if your starter relay is bad and how much it costs to replace it

car relay

It would be impossible to start a vehicle normally without the use of the starter relay. Yet, this important component is often overlooked until it no longer works.

If you are having trouble starting your car, it could be due to this part. We look at the symptoms of a bad starter relay, the function it performs, its location, and the cost to replace it. First, let’s take a quick overview of the signs to look for:

The most common symptom of a bad starting relay is that your car does not start or has intermittent starting problems. In some cases, your starter motor may remain on while the engine is running if the ignition relay is bad. You can sometimes also hear clicking sounds when you turn the key.

Here is a more detailed list of the most common symptoms of a bad starter relay:

Bad Starter Relay Symptoms

1. Vehicle Won’t Start

start engine

Typically when the starter relay dies, the most obvious symptom is that the car won’t start. Even when using electronic keys, it’s possible that the problem is the starter relay. Because these keys don’t use a manual ignition switch, the starter relay is still activated when the button is pushed.

Whether you are turning the key or pressing a button, when the vehicle won’t start, it could be the starter relay. Most often, it’s due to the failed circuit that prevents the ignition system from engaging. 

2. Starter Remains On With the Engine Running

After you start the car, you either release your key or stop pressing the button. At this time, the circuit is supposed to close and everything should continue running as normal. This closed circuit removes all power from the starter motor.

However, when the main contacts of the starter relay become welded together, it can stay stuck closed. You will know this happens because the starter stays activated even though the engine is running. You will know this is occurring based on the whining noise you should hear. 

If the starter relay remains stuck on, further damage is going to occur to other components. Not only will this problem harm the relay, but it could also damage the circuit, starter and transmission flywheel. 

3. Intermittent Starting Issues

When the starter relay works as it should, it sends power to the starter every time you engage it. However, this part can become contaminated from debris, dirt and excessive heat. These conditions can force the starter relay to work intermittently. 

If you start the vehicle and it doesn’t activate right away, but you try it again and it works, it might be the relay going bad. Thankfully, you are getting a warning that the starter relay is going bad, allowing you time to get it fixed before you are stranded. 

If the relay itself isn’t going bad, it’s also possible that there’s a faulty wire connection or one that has become corroded under the hood. 

4. Clicking Sounds 

You might hear clicking noises when the car battery is low on amperage, but it could also be a sign that the starter relay is going bad. It happens when the relay can’t send out the full signal.

Most times, the relay operates on an all or nothing basis. It’s either going to send the complete electrical current or it won’t send anything. However, when the starter relay becomes damaged, it’s possible that only a partial signal gets sent. This is what leads to a clicking sound when you attempt to turn the key. 

The Function of a Starter Relay

starter relay

The starter relay is responsible for sending high amperage to the starter motor through a low-amp circuit. This relay is responsible for powering up the starter solenoid, which requires high amperage to run. 

This amount of amperage isn’t safe to run through the ignition switch, but it must be powered whenever the switch turns to “Start.” A relay acts as a bridge and has been used in cars for decades. 

When the ignition switch is turned to the start position, the electrical power gets sent from the switch to the starter relay. There is two circuits inside the starter relay. One circuit is used to receive the signal from the switch and it keeps the other circuit closed during this time through electromagnetism. 

With this one circuit closed, power is flowing from the car battery to the starter. When the ignition switch is released, electric power ceases to the first circuit, forcing the electromagnet to open the circuit and turn off the starter. 

When the relay loses power from the switch, the circuit remains open and disconnected, and your car will not start.

RELATED: 5 Symptoms of a Bad Starter Motor

Starter Relay Location

starter relay location

The starter relay is most often located under the car hood, found in the power distribution center. It can also be located in the fuse block in the cabin.

The relay has wires coming in and out of it. However, there are many other relays used in the car that look similar. If you are unsure which one is the starter relay, reference your service manual. 

Starter Relay Replacement Cost

The average starter relay replacement cost is between $50 and $75, depending on the car model and labor costs. The starter relay parts should cost you around $20, with the labor price at $30 to $55.

Replacing a starter relay is a simple job that doesn’t require any specialized tools. If you are handy, you might prefer saving yourself some money and swapping out the starter relay yourself.

Written by:

Magnus is the owner and main author of MechanicBase. He has been working as a mechanic for over 10 years, and the majority of them specialized in advanced diagnostics and troubleshooting. He has also been a motorsport (drifting) driver for over 5 years.