ignition relays

Ignition Relay Symptoms, Function & Location

by Magnus Sellén31 Comments

Just like any other relay, the ignition relay’s job is to ensure uninterrupted electricity supply to a larger component.

The ignition relay is normally found in the fuse box situated underneath the hood and it transfers electricity from the battery to the ignition components, which allows you to start the car in the blink of an eye.

However, if the relay fails to perform up to its standards, you will start experiencing problems and not just in one, but a number of engine components such as the fuel pump and the ignition coil, among others.

Therefore, if you feel that turning the key in the ignition is having no effect on the dashboard, it may be time you get the ignition relay checked out by a certified mechanic.

What is an Ignition Relay?

The ignition relay is basically an electrical device that works as a switch for the power to the ignition system and the fuel system of your vehicle. The ignition relay is activated as soon as your turn on the ignition of your vehicle with the key.

ignition relay wiring diagram

The ignition relay then switches the power on and allows it to reach the systems that are required to be powered up so that your vehicle can function. As a result, the battery transmits the power to the ignition coil, which is then transmitted to the spark plugs of your vehicle to start the engine.

The spark plugs then cause the ignition of the fuel in the internal combustion chamber of your vehicle so that the engine can start. Typically, we do not need to replace it and the ignition relay is designed to live as long as your vehicle does. Despite this, sometimes the ignition relay can fail due to wearing, accident, damage or exposure to water.

A bad ignition relay will not only cause starting problems to your vehicle, but it can also cause stalling of the vehicle, draining and damage to the battery, and power loss in the dashboard lights. In modern vehicles, the remote starting key is used, which contains a small computer chip inside it. Ignition relay of such vehicles is more complex.

Signs of a Bad Ignition Relay

An ignition relay normally sits with a few other relays and fuses in the fuse box found in the engine bay. The area under the hood is open to contaminants and pollutants like dirt and debris – the common reason behind ignition relay failure. Even the car’s battery can destroy the relay by sending inconsistent electricity flow through to the system.

Due to all of these reasons, your car’s ignition relay can deteriorate and give you a headache when you are trying to start your car early in the morning. Fortunately, a number of symptoms can tell you beforehand if there is a problem waiting to happen or if it has already happened. We will now look into the signs of a failing ignition relay in detail.

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1. Ignition is Unresponsive

The ignition relay’s primary job is to help you start the car. The ignition itself doesn’t do anything except ushering other components such as the fuel pump and starter to give life to the car’s engine. Therefore, it is natural that if you are unable to feel anything when you turn the key in the ignition, the ignition relay is having troubles.

These issues need to be solved as soon as possible, otherwise, you will be forced to travel without your car.

2. Engine Stalls

The ignition relay not only gives life to the engine but it works as an influencer that maintains the delivery of power to the fuel pump. The fuel pump, in turn, keeps the engine running, so if the engine stalls suddenly while working, you could be looking at ignition relay failure.

However, the same can happen if there is a problem with the fuel pump or the fuel pump relay, so it is better to visit the mechanic identify the exact problem.

3. Dead Battery

All the car’s energy comes from the car’s battery, so it is necessary for the battery to work in tandem with other components; otherwise, a lot of the functions inside the car can fail. When the ignition relay fails, it can cause the ignition system to work constantly even when you have removed the keys from the ignition.

This means the circuit will not close and the battery will drain. Therefore, if you are looking at a battery that has died when it was working perfectly the day before, the ignition relay could have been the cause.

4. Fried Relay

If the ignition relay is of low-quality, it can get short-circuited pretty easily. A fried relay will affect ignition and it might even blow up due to overheating, which might also destroy the other relays and fuses in the fuse box. In which case, you will be required to change the entire fuse box.

Cleaning the Ignition Relay

The ignition relay can burn from being overused or if it gets a power surge from the battery. All this can happen due to dirt depositing on top of it or heat of the engine getting through to it. Therefore, it is necessary to keep the fuse box and especially the ignition relay sparkling clean. Here we will tell you a few ways to clean an ignition relay effectively.

Things you will need:

Locate the Relay in The Fuse Box

The ignition relay is situated in the fuse box found in the engine bay. When you locate the fuse box, open it and find the mapping on top of its lid. The key will tell you the exact position of the ignition relay as well as other relays and fuses.

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Once you have located the relay, gently pull on it to remove it from the fuse box. The relay looks like a rectangular block and is hard to miss. It can also be located inside the car within any fuse box.

Cleaning the Relay

Never use water to clean an electrical component like the relay as it can result in the relay getting destroyed completely. Therefore, always use a certified cleaner or easily evaporating liquid like ethanol for cleaning. However, first, use a blower to remove any newly deposited dirt on the ignition relay. After the blower use, using the piece of cloth, apply the cleaner and rub it gently on to the ignition relay to clean it.

You will find that this exercise does not require much effort and is easily finished within a few minutes. After you are done with the cleaning, let the relay dry for a few minutes and put it back in place.

ignition relay function

Where is the Ignition Relay Located?

The exact location of the ignition relay may differ from vehicle to vehicle depending on the design of the vehicle and the company that manufactured it. In most vehicles, the ignition relay is located in the long black box of your vehicle that you can find under the hood.

The box usually has a diagram on it which will help you easily locate the ignition relay inside it once you open it up. This box is also called the fuse box.

In order to easily locate the ignition relay and identify it properly, you may refer to the service manual provided to you by the manufacturer of your vehicle. It will be located in the relay panel along with many other relays installed on it.

How to Replace the Ignition Relay

The process of replacing the ignition relay will require you to diagnose the cause associated with the starting problem of your vehicle. If it turns out to be a failed ignition relay, you will usually need to replace it with a new one.

The process of replacement can be easy if you have the proper tools and some basic knowledge about automobile mechanics. The tools that you will generally require for the replacement include scan tools needed for diagnosis, a flashlight, ratchet sets, a boxed end wrench, a small and regular minus screwdriver, protective gears, and a torque screw set.

You can find most of these tools in your workshop easily. Once you have the tools and the new ignition relay ready with you, you can start the replacement process. Here is a step by step easy to follow guide on how you can effectively replace the old and failed ignition relay of your vehicle with a new one.

  • Remove the cables from the battery terminals to cut off the electric connection
  • Remove the bolts from the steering column of your vehicle
  • Remove the dashboard covers until you can assess the area
  • Locate the ignition relay which is connected to many components
  • Refer to the service manual in order to correctly identify the ignition relay
  • Remove all the electrical connections from the ignition relay
  • Remove the bolt from the cover of the relay switch
  • Remove the screws from the steering column that is holding the ignition relay
  • Make sure you remember each step
  • Pull out the ignition relay
  • Compare the ignition relay with the new one that you bought
  • Install the new ignition relay in the same place, reversing the steps
  • Reconnect the electrical connections in the same way that you removed them
  • Reconnect the screws back to the steering column and ignition relay
  • Reconnect the bolts to cover the ignition switch
  • Cover the dashboard again with the covers
  • Install the steering column again that you removed
  • Connect the cables to the battery terminals that you removed.
  • Run the error codes to clear them with the scan tool
  • Fix everything back in place and test your vehicle
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How to Diagnose a Bad Ignition Relay

To see if the ignition relay has failed, you can test for a voltage drop or you can test for electrical resistance. Here is a quick and easy to follow testing and diagnostic procedure for finding out if the ignition relay has failed.

  1. To test for a voltage drop, set your multimeter to 20V DC
  2. Connect the black probe of the multimeter to the ignition switch circuit
  3. Connect the red probe with the red battery wire
  4. Ask someone to turn on the ignition
  5. See if the voltage drop is less than 0.2V
  6. If it is more than 0.2V, your ignition relay has failed
  7. For the electrical resistance test, the readings should be less than 5 Ohms for a properly functioning ignition relay

31 thoughts on “ Ignition Relay Symptoms, Function & Location ”

  1. Hi am having a ford ranger 2017 diesel ,I was driving and the car just stop .what can be the cause?

    1. Awesome information very detailed and to the point. Thank you! Keep up the good work!!

      1. its 91 ford f350. thought it was the fuel pump, replaced it and the fuel pump relay, ran great for one week now just flat wont start. fuel relay? ignitipn relay ? please help

    2. 1998 crv car starts easy but when gets real hot and you turn off engine won’t start till motor cools down.

    3. Says relay is in fuse box more than likely but to replace they say take out steering colum and dashboard….someone needs more schooling

    4. I lost my keys to a 1999 toyota avalon i had a fob key made at toyota dealership i programed the key it works but i have a problem it will crank but it wont start thinking it the anti theft but could it be the ignition relay

  2. Why my car stall at prolong traffic. Is this also related to a BAD relay?

    1. You need to run a return fuel line from ur carb
      So it stops the built up gas sitting there in the cooking heat in traffic from vaporizing- called valor lock- check it out and research bet it is that

  3. I went to O’reilly auto parts store and they have me a black relay switch to put in, in the fuse box. Which one will it replace?

  4. When driving I can feel the car stalling. When I stop, turn off the car ignition, engine still running, stalling for a minute before it stops even if I have already removed the key from ignition.

    1. I have a Ford ranger 3.0 v6. I was driving in the day with headlights on during a severe snowstorm. Parked truck and left lights on. Tried to start next day. No crank, no click on solenoid. Battery dead. Got jump and started. Went on errand. Parked and returned to vehicle. Truck would not start. Got battery charged slow overnight at a auto parts store. Got 660cca on test. Tried to start no crank, no click on solenoid.

      On all attempted starts battery fully discharged completely drained instantaneosly. How did leaving my lights on cause this permanent problem. What should I do to find cause and fix it.


    2. One day I took the auxiliary ignition relay my car did start when I try it again only swinging

  5. I forgot to give you the year of my ford ranger 3.0 v6 it is a 1994. On no crank, no click on solenoid after lost all battery power instantaneously upon trying to start.

  6. i have a CRV RD1 which stalls every day when i drive around. after waiting for 5 to 10 minutes the car starts again. it happens twice or three times a day. is it a problem related to bad iginition relay? please help me solve this problem.

    1. hi mate look for a sensor located under the thermostat housing one is the temp sensor and the other one tell the ecu if the car has overheated and puts it in a no start situation change this sensor

      1. Change this part Engine coolant temperature (ECT) sensor do not change this part
        Coolant temperature gauge sendlng

  7. When you replace 1 tr engine with 1rz engine what else are you suppose to change apart from harness cable.

  8. I am driving a hyundai i30. All of sudden there’s no spark but it cranks. I changed a crank sensor but it still no spark at all. What can it be?

  9. Hello

    I have a Ford Fusion sel 2011 no power When I turn after waited 30 minutes turn on. What would cause this symptom

    1. Hi am Richard I just replace the module of Hyundai accent 1998 1.3 the car crank by doest want to star .were can I find the relay for starter pls help

  10. Hello, my Honda Civic 2008 keeps showing a constant green key blinks on the dashboard and as such cannot ignite or start the car. Please what is the cause and what can I do to rectify it?

  11. What would make a 2006 Ford focus die and then not restart. Getting gas, new crankshaft sensor, no fire since it died, any suggestions gotta get it fixed gave to take wife to airport on 9th, and needed for work thanks for any suggestions

  12. 1997 Maxima. Turns over but will not start. Getting fuel and spark just won’t start. Also drained new battery after sitting for two days. Found a relay labeled security/start. Should I replace this relay. Or other possible bad relay?

  13. Hi
    I got a Ford Mondeo diesel 2011 model
    Keyless start push button, soon as I press the push button there is no ignition. There is a message steering lock malfunction I have check all the fuses & relay they all are good.

  14. my 06 dodge charger reads a code u0101 loss communication and the battery drains ita a no crank no start do i need temp sensor and ignition relay

  15. I have a 2002 Jeep Wrangler. Is the ignition relay and starter relay the same thing. Not finding one marked ignition, only starter.

  16. My f-150 ford truck failed emissions do to module was not connecting to their computer when they connected their device to my truck could it be a bad relay

  17. Hi there i am trying to locate the ignition relay of my Opel Corsa utility 1.4 2008, can someone please help me.

  18. Key less 2014 fiesta 1,6 diesel when pushing start button it just clicks and car won’t start battery alternator starter motor all checked and ok what could it be thinking relays? What you think next move is

  19. Due to a very high demand and high ammount of comments, you have to wait for some time for your car questions to get answered. If you want to get fast answers from a certified master technician you can ask your questions here:
    Ask A Mechanic

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