4 Symptoms Of A Bad Starter Relay (& Replacement Cost)

#1. A Car That Fails To Start

Failing to start the car is one of the main signs that a starter relay has become damaged and needs immediate checking.

If you switch on the ignition and the car remains silent; no clicking, not anything, it means there’s no current flowing through the relay’s coil. So the coil doesn’t magnetize strongly enough to attract the armature to switch on the battery circuit.

The end result is zero current flowing through the starter solenoid and the starter motor, and the engine cannot start.

Switch on other car accessories or devices that use the battery to confirm if the battery is working and in good condition.

If the battery is confirmed not to be dead, the starter may need repair or total replacement.

Video

2. Starting relay function

Between the vehicle’s battery and the starter motor, the starter relay acts as a circuit completer or circuit breaker. It helps to increase the battery’s current so that less current needs to be ignited. According to the description, this is a switch between the start solenoid and the start motor.

When you turn the ignition key or press the car’s start button, a large current is generated. The starter motor requires considerable current, and the ignition switch cannot be controlled. If there is no relay, it will burn out.

If the starting relay fails, the vehicle may not start. As we will see later, there are many reasons why this component may fail. They also require various treatments according to the nature and severity of the hazard. Some can be repaired, and some require the installation of new relays.

FAQs

You may still have questions about starter relays, so let’s review some more commonly asked questions on the subject.

How to bypass the starter relay?

While starter relays are essential to turning over your engine, there is a way to bypass the fuse. Using the metal blade of an insulated screwdriver, place the metal blade across both metal contacts. The metal will allow the electrical current through without the starter relay. 

How do I know if my starter relay is good?

If your vehicle starts without any issues and runs smoothly, you most likely don’t have a bad starter relay. However, you can test your starter relay by checking the voltage and electrical resistance.

Why is my starter relay buzzing?

A buzzing starter relay typically indicates a bad fuse. If your relay is buzzing, your fuse may have experienced failure or you have a bad switch connected to the relay. You can determine what is causing the starter relay to buzz by testing the fuse.

How Does a Starter Relay Work? How Does it Work With Starter Solenoid and Starter Motor?

A starter relay is used to send a signal from the ignition to the starter solenoid, which in turn activates the starter motor. The starter relay typically has four terminals: one for the battery, one for the ground, one for the ignition switch input, and one for the output to the starter solenoid.

When the key is turned to the “start” position, current flows through the coil, activating the electromagnet inside. This attracts a switch arm or plunger, closing a circuit and allowing current to flow to the starter solenoid. The solenoid then activates the starter motor, which turns over the engine.

Similarly, when the key is turned to the “off” position, the current stops flowing to the coil, which deactivates the electromagnet. This releases the switch arm or plunger, opening the circuit and cutting off the current flow to the starter solenoid.

So, you can see that without a properly functioning starter relay, a vehicle will not be able to start. If you suspect that your starter relay may be faulty, it is essential to have it checked by a professional as soon as possible.

How To Diagnose Replace A Bad Starter Relay?

Now as we covered the bad starter relay symptoms, let’s now focus on something else. Namely, the diagnostic process as well as the replacement of this important relay.

The first thing you need to do is to learn if this is a relay-related issue. So, if the accessories inside of the car are working perfectly well and you have trouble only with starting the engine, then this for sure is a problem with either the solenoid or the relay.

If the solenoid is the one that is bad then you will highly likely get a clicking noise. If the relay is bad then there will be absolutely nothing in 99% of the cases. So, in this case, you might be wanting to check the fuse box and locate the relay based on the information on the cover.

Once located the relay, just remove it from its position and now you can test if the relay is working or not. You can do this with a multimeter tool and a small battery. You just need to check if there is resistance whenever there is power to the relay.

If there is, then the circuit is closed. If there is no resistance, the circuit is open and the relay is not performing as it should. For a visual way of how you can learn this process, you can watch the video that we attached.

If you determine that the relay is the problem, then you will only have to get a new one from your local parts store. Just make sure that you get the exact relay for your application. Not all relays are the same. Beware of this fact. But what is the cost to replace a relay? Let’s find out next.

How Do You Test a Starter Relay on a Motorcycle?

As we mentioned above, the starter relay is the component in your starter system that relays power from the battery to the starter motor. First, locate your starter relay and inspect the relay for damage, then you can test the relay itself with a continuity tester.

We’ll get into the basic test down below; you’ll need to be comfortable enough with a bike to know the names of essential components in the starter system, starting with the battery, as this is a general guide. Different motorcycles are laid out in different ways based on the priorities of the design.

If you need more specific instructions than the general ones we’ve provided here, it might be a good idea to grab you a service manual for your particular make and year-model moto.

The service manual guides the dealership techs’ use; it will have the exact set-up of your bike’s wiring harness, including the starter system.

Remember, if you don’t have the tools or space needed to conduct the following procedures or if you can’t find access to a service manual and you’re unsure about your working knowledge, any decent bike tech can do this test on the fly for pretty cheap.

  1. Step 1: Locate the starter relay and examine your starter relay’s 30 amp fuse for any indication of corrosion. Swap out the fuse if it’s looking rough.
  2. Step 2: Attach the black jumper wire from the negative battery terminal to the green or red wire of the starter relay.
  3. Step 3: Fasten the red jumper wire from the positive battery post to the starter relay’s yellow or red wire terminal. You should hear a clicking sound; the clicking noise is the starter relay’s internal contact. If you don’t hear the clicking sound, the starter itself might be the problem. Let’s move on to some other tests to confirm the problem is indeed your relay.
  4. Step 4: Detach the red jumper wire from the starter relay as soon as you finish with the third step. 
  5. Step 5: Hook your Continuity Tester’s wires up to your starter relay’s battery terminal and starter motor terminal. Read the labels to tell which is which. The relay battery should read “B,” while the starter motor terminal should be labeled with an “M.” Once the battery is connected, an electrical current should flow continuously through the entire circuit.
  6. Step 6: Monitor the gauge needle on the Continuity Tester to read if your flow is continuous. Note: If there was no clicking noise during Step 3 and there’s no continuity during step 6, you’ve got a faulty relay, and there is no continuity when the battery is connected, the starter relay in your motorcycle is busted.

Related: Motorcycle Clicks Instead Of Starting: 3 Reasons (Solved)

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Conclusion

In this article, we have covered quite a bit when it comes to the starter relay. We first learned what this relay is and why it is so important. Without it, you will basically not be able to start the vehicle. It is that crucial.

Then we covered the symptoms of a bad relay and learned what can you expect when you have a bad relay. And the answer is that the engine will not like to start.

Then we learned how you can diagnose the problem and replace this component. As well as how you can bypass this component as well.

How to Test a Bad Starter Relay?

A bad starter relay can cause your car to have a hard time starting or not starting at all. Here is the list of all the equipment and supplies you need to test a bad starter relay:

  • Safety gear
  • Digital voltmeter
  • Charged car battery
  • Jumper Cables
  • Wire Brush
  • Water and Baking soda

Now, let us see the detailed procedure for testing a bad starter relay:

1. Park Your Car Properly:

You must park your vehicle on level ground before starting the testing process. This will help you avoid accidents while working on the car.

2. Put On Your Safety Gear:

Make sure you wear all the necessary safety gear before working on the car. This includes gloves, goggles, and ear protection.

3. Disconnect The Negative Battery Cable:

The first thing you need to do is to disconnect the negative battery cable from the battery. This will prevent any electrical shocks while you are working on the starter relay.

4. Gather Supplies:

Now, you must gather all the supplies you will need to test the starter relay. This includes a charged battery, jumper cables, baking soda, water, and a wire brush.

5. Check The Battery Connections:

Now, you need to check the battery connections to make sure they are clean and tight. This can be done using a wire brush to clean any corrosion off the terminals. Once they are clean, you need to use a voltmeter to test the voltage of the battery. It should be around 12 volts. If it is not, then you will need to replace the battery.

6. Locate the Starter Relay:

After ensuring that you have a strong enough battery, the next step is to locate the starter relay. It is usually located in the fuse box under the hood of the car. Once you have found it, you need to remove its wiring. But make sure to tag each wire upon removal. This way, you will not forget the sequence when you put them back.

7. Test the Starter Relay:

Now, it is time to test the starter relay itself. You can do this by following this procedure here:

  • Locate four terminals on the relay. One of these is the ground terminal (85), another one is the input terminal from the ignition switch (86), one provides power from the battery (30), and the last one is the output towards the starter solenoid (87).
  • Once you’ve established which terminal is which, now start the process of testing the relay.
  • Energize the relay by providing power to the terminal connected to the battery. You can use a jumper wire for this.
  • Using another jumper cable, you must connect the ground terminal of the starter relay to the chassis of the car.
  • With the help of a digital voltmeter, measure the resistance value between terminal 30 and 87.
  • The expected value should be around 0.5 ohms. If the value is not as expected, then the relay is bad and needs to be replaced.

8. Clean The Terminals:

Once you have tested the starter relay, you need to clean the terminals on the relay using a wire brush. This will help to prevent any corrosion in the future.

9. Put Everything Back Together:

The last step is to put everything back together in the reverse order you took apart. Make sure to tighten all bolts and put the wires back in the correct sequence. Once everything is back together, you can try starting the car to see if the problem has been fixed.

If you follow these steps, you should be able to test a bad fuse box starter relay and fix any problems that you may find. But, if you are still having trouble starting your car, you may need to take it to a mechanic for further diagnosis.

#3. The Starter Relay That Remains on, Even After The Engine Has Started

When you switch on the ignition key, the starter relay switches on, and the starter motor and starter solenoid begin operating.

Switching off the ignition key or button should have the opposite effect: the motor and starter solenoid should stop operation.

If this doesn’t happen and the starter relay remains on even long after the engine has started, the relay is faulty.

It could be that the relay’s contacts have welded together, something that happens from exposure to high currents over time.

You should take immediate action because this kind of fault can result in damage to the whole starter system.

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