Honda Civic Main Relay Symptoms: Let’s Fix this Honda Civic Main Relay

The efficient functioning of the main relay of a vehicle is vital to get the proper working of the engine.

If you doubt that your Honda Civic engine is not working correctly, you will have to look through Honda Civic main relay symptoms to determine where the problem is.

In case your vehicle’s central relay system is not supplying the power that it is intended to, your engine will not operate properly at all.

The main relay system makes sure that the engine’s computer is provided with the needed energy.

What is Honda Civic Main Relay?

The Main Relay of a vehicle is responsible for controlling the fuel pump and supplying power to the injectors. The engine computer is a vital part of any vehicle’s engine.

It contributes to the engine’s proper functioning, and the main relay supplies power to it—also, the main relay powers the whole fuel system of a vehicle.

If your engine computer is not working correctly, there is no chance that your car’s engine will function as it is intended to.

And the main relay is an essential component of the engine’s computer as it is responsible for providing adequate power to it that is essential for its proper working.

If the main relay is not working correctly, you will have to address it immediately and solve it before it affects the engine.

Therefore, you will have to maintain your Honda Civic main relay if you want to avoid any instability.

Honda Civic Main Relay Symptoms: Crucial Symptoms

As the main relay of a vehicle is exposed to high heat, it gets damaged over time. The damage should be determined and repaired immediately as it leads to various severe problems in the vehicle.

Although it is difficult for an average car owner to resolve the main relay symptoms, some symptoms can help.

If you don’t have any professional mechanic nearby and want to know what is causing the instability in your Honda Civic, here are some main relay symptoms.

These symptoms can effectively help you determine whether it is the main relay causing this instability. The symptoms of a malfunctioning main relay are described below;

1. Engine not starting

The car’s main relay is responsible for providing power to the whole fuel system of the vehicle.

This means that if your main relay is not working correctly, the fuel system is not getting the power that it requires for functioning. In this case, your engine will not crank or even work correctly.

Even though this can be a case due to certain other factors, including no fuel in the car, it is appropriate to get the main relay checked.

If you are sure that the main relay is causing problems in your engine, you should immediately contact and diagnose the problem.

You will need to consult a mechanic because the diagnosis process is complicated and time-consuming.

2. The car cannot run continuously for a longer time

If your main relay is not working correctly, your car will regularly crank, followed by a dead engine immediately afterward.

This is your call to get your vehicle to the mechanic and get your main relay checked.

Even though the main relay testing is very time-consuming and challenging, you should not risk your whole car for this at any cost. You can identify this problem by taking guidance from this video.

It is not only annoying and frustrating if your car is continuously cutting off at regular intervals, but it also is very much dangerous.

Also, if your Honda Civic’s main relay cannot be repaired, you should necessarily replace it with a new one before your car becomes unusable.

3. The car engine starts perfectly sometimes while sometimes it fails to start

If you face such discontinuation in the working of your car’s engine where sometimes it starts perfectly while sometimes it fails to start, you need to get your main relay checked.

This can be a case if your main relay works appropriately at the time, providing the necessary power to start the engine.

While other times, it starts to malfunction, not providing the necessary power or any power. You should not waste any time and get your main relay checked immediately in this case.

Because your car can stop anywhere or anytime, and you might not have any mechanics nearby. So, if you observe this symptom in your vehicle, consult an expert and fix it immediately.

4. Check if your engine light is on

If your engine light is turned on, you should know that it is time to get your main relay checked.

This can be sure to various malfunctioning reasons that you should diagnose and get fixed quickly. An OBD or OBD-II scanner is present in most of the vehicles that display a diagnostic code.

This code enables you to identify the problem immediately.

However, if you are unaware of how the OBD or OBD-II scanner works or how the codes are displayed, you should consult a professional right away.

You will have to visit a mechanic or a shop that possesses diagnostic equipment to help you determine the root cause of what has made your engine light lit.

5. The car will not start in case the temperature of the car’s interior increases

If your car’s main relay has had problems, another symptom is that your vehicle will not start once your car’s interior gets hot.

This can be due to the situation in the circuit path, as heat is responsible for the dislocation of solder joints to the relay.

If you do not address this problem instantly, it can cause more damage to the main relay of your vehicle. So, it is vital to get your car checked by a professional to identify and solve any problem.

How to Fix Honda Civic Main Relay Failures

Although it is pretty tricky to diagnose a failing main relay, you can still diagnose specific malfunctioning.

If you have been able to diagnose the problem in your Honda Civic main relay, you can fix it for yourself if it is not as big or doesn’t require a replacement.

Usually, the diagnosis is complicated because the problem can be from air or fuel, spark plugs, or even fuel pumps.

After you have made the diagnosis, you will have to check for the appropriate solutions. You will have to see if you can do the repairing on your own or will you have to go to a professional.

You can get the diagnosis done by following the below-mentioned things;

Tap on the Relay

If you want to check your main relay, you can pat on it a couple of times. It starts working after the patting, your main relay has a problem, and you need to check it.

The professional will be able to tell you whether your Honda civic main relay requires repairing or a replacement.

Inspecting the first clicks after starting the car

To diagnose your main relay, you can do three clicks with your key at certain positions.

If the cars don’t start at the third click, or you do not hear any of the previous clicks, there is a chance that your main relay has a problem.

Make sure to get it checked instantly or get it replaced if necessary.

Honda DIY Main Relay Fixing: The Process

You can get your Honda Civic main relay fixed by yourself by following the below-mentioned steps;

1. Disconnect the negative cables

Before repairing the main relay, you will have to disconnect the negative cables on the battery.

2. Removing fuse panel

Now, remove the fuse panel and lower the driver side’s dash panel using a screwdriver.

3. Remove the main relay bracket.

Once the main relay of your car is exposed, you will have to remove its bracket, which is held by a 10mm bolt. Use a wrench to remove this bolt.

4. Unfasten the wire harness

Now, it is time to unclip the attached wire harness.

5. Do some soldering

You might be seeing some cracks around solders on the metal post. This video can help you effectively to repair your Honda main relay.

You can also remove the solder from the weak joints and replace it with new ones if necessary.

6. Reattach the main relay

Now, follow all these steps backward to get your main relay back on. This will be a straightforward step.

Honda Civic Main Relay Location

The Honda Civic main relay is located underneath the hood of a car in a relay box. In some models of vehicles, the main relay is located beneath the dashboard.

In Honda Civic, a fuse box covers the main relay, and it can be found on the left side of the steering wheel.

You will come across a small seam or a crack along with the dashboard that you will have to open using a screwdriver. This is where your main relay will be.

Crucial FAQs for the Honda Civic Main Relay Symptoms

1. What makes the main relay go bad?

If the main relay of your vehicle is being operated at a high load, it will fail as its contacts will not be able to work efficiently.

Also, when surprising high path resistance occurs, the main relay of your car can go wrong or fail. On average, the main relay is suitable for 100,000 operations and will have to be replaced.

2. Does a bad relay click?

If you have a faulty starter relay, the electrical signal will not reach the starter motor from the battery. Therefore, your car will produce a clicking sound every time it gets started.

This means that you probably have a bad relay, and you need to get it checked immediately.

3. What does the main relay do in a car?

The main relay is responsible for opening and shutting the fuel system of the car. In some cars and car models, the main relay also manages the ignition system.

Also, it is responsible for providing the power to the engine computer that is necessarily required to run the engine smoothly.

4. Will a bad relay cause no spark?

If the fuel pump of your car is not priming and is not leading to any spark, it can be due to various reasons;

  • A bad relay
  • A blown fuse, either relay or ECU
  • Bad ground thermostat housing connection

If there is not a spark, you can also check the coil, igniter unit, or timing belt.

5. How long does a fuel pump relay last?

A fuel pump relay is known to be last for approximately 160,000 km to 300 000 km on average.

After your relay has undergone this mileage, you will have to replace the main relay instantly before it starts causing further instability.

6. How much does it cost to fix a relay?

The repairing cost of the main relay can differ from location to location and from vehicle to vehicle as well.

On average, the labor asked for fixing the main relay is around $30 to $38, while the replacement parts cost approximately $30 to $35.

7. How much is a Honda main relay?

The price of the Honda main relay might vary from model to model. But on average, the Honda main relay costs around $75 to $85.

8. Where is the fuel relay switch located?

The fuel relay switch is located under the dashboard and close to the steering column in most vehicles.

In some cases, the main relay can be located close to the engine’s firewall and even in the region where the steering column is usually mounted.


The main relay is a crucial component of the vehicle that ensures proper functioning of the car.

As it is responsible for providing the necessary power to the whole fuel system and the engine computer, its malfunctioning cannot be ignored.

If you miss the minimum Honda Civic main relay symptoms, it will lead to severe problems within no time, and your whole car will become unusable.

Therefore, it is necessary to get the main relay of your car fixed or replaced right away to avoid other engine problems.

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