5 Symptoms of a Bad Ignition Relay (& Replacement Cost)

The ignition relay may seem like a small part, but it is actually very important and without it, you wouldn't be able to start your car. Here are some more signs to look for

fuse box relay

The ignition relay’s job is to ensure uninterrupted electricity supply to many of your car’s components.

The ignition relay is usually found in the fuse box situated underneath the hood or somewhere under the car’s dashboard. 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 many engine components such as the fuel pump and the ignition coil, among others. So what happens if you have a bad ignition relay?

The most common symptom of a bad ignition relay is an unresponsive ignition switch. You can also notice signs like engine stalls or a dead car battery in the morning. In rare cases, you can also feel a burnt electronic smell.

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.

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

Bad Ignition Relay Symptoms

1. Ignition is Unresponsive

ignition switched on

The ignition relay’s primary job is to give power to all control modules and sensors in your car needed for the engine to run.

If nothing happens on your dashboard when you turn the key in the ignition lock, and you are sure that the car battery is charged – there is a big risk that something is wrong with the ignition relay.

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

RELATED: Symptoms of a Bad Fuel Pump Relay & Location

2. Engine Stalls

engine stall

The ignition relay supplies power to essential engine parts like the fuel pump and the ignition coils. Without these components, your engine will die imminently, so you can probably guess what will happen if it can’t deliver power to them.

If your car shuts off while driving, the ignition relay can be to blame.

3. Fluctuating Ignition power

table flipper game

If your dashboard is blinking like a table-flipping game, there may be an issue with the ignition relay.

Situations occur when there becomes corrosion inside of the ignition relay. This can cause the connection area inside the relay to become too small – which will cause the ignition to shut off and on super fast.

RELATED: Symptoms of a Bad Main Relay

4. Dead Battery after night

jump start

When you switch off the ignition key, the ignition relay should also shut off power to all engine components; otherwise, it will drain the car battery when you let the car stands over the night.

When the ignition relay fails, it can cause the ignition system to be activated constantly, even when you have removed the keys from the ignition.

This means the circuit will not open after you remove the key, and the battery will drain.

Therefore, if you are looking at a battery that had died when working the day perfectly before, the ignition relay could have been the cause.

5. Bad electronic smell

bad smell in car

Bad connection when it comes to electronics creates heat. An ignition relay with corrosion, rust, or water inside of it can get a bad connection inside it, and this will cause a lot of heat.

Often you can see that the plastic cover melted over the relay even. If you have experienced a burnt electronic smell before – you should absolutely check the ignition relay the next time you can feel it.

What is an Ignition Relay?

ignition relay wiring diagram

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

The ignition relay then switches the power on and allows it to reach the systems 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 your vehicle’s spark plugs to start the engine.

Where is the Ignition Relay Located?

ignition relay location

The ignition relay is often located in the fuse box under the hood. It can also be located in a fuse box under the dashboard inside of the car.

The ignition relay’s exact location may differ from vehicle to vehicle depending on the design of the vehicle and the company that manufactured it.

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

Ignition Relay Replacement Cost

The average ignition relay replacement cost is between $15 and $100, depending on the car model and labor costs. An ignition relay costs $5 to $50 and labor costs $10 to $50.

The ignition relay itself is often very cheap, and you can expect it to cost under $10, depending on if you want to buy an OEM original one or aftermarket.

The replacement of the ignition relay is also often very straightforward. You can expect a replacement cost of $15 to $100 if you want a mechanic to do it instead.

Testing the ignition relay

The ignition relay is often pretty easy to test depending on the relay type. Most ignition relays have 4 pins, and if you have one of these, you can follow this guide.

  1. Remove the ignition relay from the fuse box.
  2. Get a couple of cables and locate the car battery.
  3. Check the relay’s backside for numbers; you will probably find 30, 85, 86, and 87.
  4. Remove the relay from the fuse box.
  5. Connect 12 volts from the car battery directly to the pins 30 and 85.
  6. Ground the 86 pin from the ground on the car battery and you should hear a clicking sound from the relay.
  7. Check with a multimeter if you got 12v+ on the 87 pins. If you don’t, your ignition relay is broken.
  8. If you do there can still be a problem in the relay, but you need to load-test it to find the problem. The easiest thing to load-test the relay is testing something that draws a lot of power through the pin 87, like a fuel pump or something similar.

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.