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Ignition Relay Failure Symptoms


Ignition Relay Failure Symptoms

An ignition rely failure doesn’t happen often but it can cause big problems when it does strike your vehicle. Fortunately, it doesn’t take a lot of time or money to fix. 

Ignition relay failure symptoms include a chronic dead battery, a burning smell from a melted relay, car stalling or not starting at all. While one of these signs isn’t conclusive you have a bad relay, several lumped together point to a faulty relay switch as the problem. 

It’s important to understand the various signs of all these problems to figure out if its the ignition relay or something else.

Read on to find out more about how a bad ignition relay can affect your car. 

Main Symptoms of a Bad Ignition Relay

Drained Battery

Are you constantly needing to jump off your car in the morning? You could either have a bad battery or a faulty ignition relay. 

The first, and easiest thing to do is check your battery to see if that’s the problem. Some batteries have cells that cease to hold power and may be out of warranty. You can take your battery to an auto retail shop and have them recharge it. They will check it and tell you the condition. A full recharge will take 24 hours but it’s free.

Look to the ignition relay once you’ve cleared the battery as the culprit. It could be draining your battery every night. 

Here’s what happens:

A good ignition relay will turn off the current and power once you turn off the car. A bad ignition relay won’t cut the power. In essence, your car is on all night using power even though you’ve turned it off.

That is what’s draining your battery. 

Read: How Long Can a Car Battery Sit Unused?

Burned Relay

Sometimes, a relay overheats, burns, and melts. It can melt on the fuse panel. You will know this is the problem by a constant smell of plastic burning as the outer housing of the relay is often plastic.

The smell is obvious and pretty horrific.

This problem will prevent power from getting to your engine, causing bad performance, stalls, and trouble starting. 

A burned fuse is hard to remove. You probably will need a mechanic to do it and may need to replace the entire fuse box. 

Car Stalling

A stalled car is never a fun thing, especially if you’re driving on a highway when it happens. Eventually, a faulty ignition relay will completely give out and that will cut power to your car. That causes it to stall. 

Stalling could indicate any number of issues from a clogged fuel line to an air intake issue but it likely is an ignition relay if it happens while driving. 

Read: 5 Reasons Why A Car Engine Knocks On Startup Then Goes Away

Car Failing to Start

Chronic problems starting the car is another symptom that you have a bad ignition relay. The first thing to check is the battery to make sure it’s working. After that, look to the ignition relay. 

A hard-to-start car doesn’t always mean you have a faulty ignition relay but this is likely the issue if there are other associated problems like your electrical is going crazy off and on or if the starting is random. 

It doesn’t hurt to have your relay tested and replacing it should be a part of routine maintenance. Aging relays just stop working for no apparent reason at all. 

Read: Does a Car Battery Drain Faster In Cold?


Most mechanics check the ignition relays when they do a complete electrical inspection. This often is part of a routine inspection. Check your maintenance schedule to see when it’s supposed to happen. 

If your car is giving your problems now, you can always ask your mechanic to check your ignition relay and give your electrical system a look. 


The Cost of Replacement

Replacing an ignition relay is cheap and simple. Relay switches cost anywhere from $5 to $100 and there isn’t more than a half-hour of labor involved so that cost will range between $35 and $75, depending on the hourly fee your mechanic charges. 

Cost also depends on the make and model of your car as parts for different models can vary.


Where is the ignition relay?

There are two places the ignition relay can be found in vehicles. The first and most common place is in a fuse box under the hood. The second place is in a fuse box found under the dashboard inside of the vehicle. 

What is the ignition coil relay?

The coil is the electromagnetic part of the ignition relay. The ignition relay is what provides power to your car’s ignition system and also some of the fuel systems. Sometimes the coil fails and that means your car won’t start. 

Is an ignition relay the same as a starter relay?

No, although some will use the terms interchangeably. An ignition relay has a low-powered signal that starts the engine. The ignition relay signals the starter relay or solenoid and that relay activates the starter by switching on the starter circuit. 

How do you use a relay?

A relay can be used when something needs to switch from high to low current, or the other way around, within the same circuit. An example would be some sensors for heating and air units may require more power than exceed their wiring capacity. 

Why do cars need relays?

The purpose of relays is to automate power to switch various circuits off and on when needed. 

Why do relays fail?

Relays can fail because they overheat from high voltage splines or high amounts of current coming through constantly. They can also fail because they have poor contact alignment or corrosion has gotten so bad it limits the connecting space. 

Open coils can be another problem causing a relay to fail. 

Can a relay that clicks still be faulty?

No, if a relay clicks it isn’t the problem. The wiring isn’t the issue either. However, if it doesn’t click there could be an issue inside the relay or in the wiring. Polarity doesn’t matter because it will energize anyway. 

Do LED lights need a relay?

A light pod without a large amp draw probably doesn’t need a relay switch. However, a large LED light bar will need a relay. 

How do you know if the problem is your starter or the ignition relay?

First, check your battery to see if it’s fully charged. Next, check all your inside accessories like your horn, interior lights, door locks, flashers, and headlights. Also, check your radio, turn signals, and wipers. Look to see if the lights dim when you try to crank the car. 

You will check the starter first. Do that by turning the key on and them using a voltmeter to check the power leading to the starter. A positive verdict on the power means you have a bad starter. 

Next test the ignition switch by putting the key in the run or acc position. Check to see if you are getting powers to fuses and then power to pins 1,7, 3, and 2. If they’re okay, then look at the power going to pin 8 while in the ACC position and check pins 10, 9, and 8 while the key is in the run position.

No power to these pins indicates the ignition relay switch is faulty and should be replaced.

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