Starter relay fuse symptoms — causes and fixes

When having trouble starting the car, most drivers instantly think there’s something wrong with the battery. Still, there are many other components of the car starting system, and the problem could be as simple as a blown fuse.

So, if you are having a problem with a blown starter relay fuse, the starter motor won’t be able to crank the engine and give the initial spin to the flywheel. This problem might appear as something far worse, like a dead battery or a bad starter solenoid. So let’s see how you can see it for what it is and fix it as soon as possible.

The role of a starter relay in your car

Before we get to the mechanics and what happens if there’s a blown starter relay fuse, let’s take a few moments to describe the importance of the starter relay itself. The starter relay is a part of your car’s starting system that also consists of the starter motor and the solenoid.

The starter motor helps rotate the crankshaft for the first time as you start your car since it spins the flywheel and engages air intake and fuel delivery into the chambers. To do this, the starter motor requires a vast amount of electrical power, which is why some drivers often confuse its bad performance with a dead battery.

However, the starter doesn’t use the power of the battery alone in this process – the starter solenoid receives an electric charge from the battery and converts it into a higher power. The starter motor uses the power from the solenoid to engage the rotator and move the starter’s pinion which eventually triggers the flywheel. That’s why it’s possible that the car won’t start but the lights turn on since the starter motor won’t work even if the electric current flow is achieved.

So, where does the starter relay fit in when it comes to this scheme? Well, the relay is responsible for transferring the power from the battery into the solenoid. It acts as a switch for the circuit without which the cycle couldn’t be completed and the starter motor wouldn’t have enough power to engage its pinion.

As you now know, without this action and the starter motor rotator which generates torque for the pinion, the engine’s flywheel can’t be engaged. If you have a bad starter relay or a blown fuse, the switch won’t be able to transfer electric charge from the battery to the solenoid.

Difference between a blown fuse and a bad relay

Since the relay is a switch that completes the starting system’s circuit and power distribution from the battery, it must stay functional. However, two problems could make it useless in your car – relay malfunction or a blown fuse.

The starter relay fuse acts as a safety measure in your car to prevent the vehicle’s parts from catching fire under short circuits or electrical issues. If there’s a blown fuse, it could be due to a problem with the power supply within the relay and the starting system of the car.

Replacing the fuse will sort out this problem since it’s not a matter of a bad relay itself. Still, if the relay wears off, it’s a far worse problem since you’ll need to replace the relay for the starter motor to work again.

Signs of a blown starter relay fuse

Luckily, there are some signs of a blown starter relay fuse that could get you on the right track when dealing with the issue. While they often resemble symptoms of a bad starter, it’s simply due to the vital function of the relay for powering the starter motor.

• Clicking sounds when starting the car
• The starter relay stuck in the position
• The vehicle sometimes starts and sometimes not

If your car sometimes starts and sometimes won’t, it’s a problem that’s associated with a bad starter motor. However, a blown fuse will also result in the same problem. You might hear a series of clicking sounds without any cranking while trying to start your car.

Still, one situation that suggests a problem with the starter relay is the switch that’s stuck in position.

Stuck starter relay

The role of the starter relay is to be a power switch between the battery and the starter solenoid. So, when you turn the key in the ignition, the switch stays open to let the power charge through to the solenoid. However, the power supply cuts as soon as the engine starts, and the relay closes.

The problem occurs when the starter relay stays stuck open. If this happens, the continuous electric charge could result in a short circuit and the charge could damage the solenoid or the starter motor itself.

A blown fuse could cause the starter relay to stay stuck open, and if it results in the fried solenoid or starter motor damage, you’ll probably sense a wire-burning smell.

Fixing the bad starter relay fuse

If the fuse problem has caused your starter relay to stay forced open, it’s easy to diagnose and fix the issue. The first thing you should do is check your car’s fuse box. It’s mostly located under the hood for newer vehicles, or on the interior of the car near the steering wheel or the pedals in older vehicles.

You can refer to the owner’s manual to find the fuse box and check for blown fuses. By simply doing so, you can find the blown fuse and replace it to get your starter relay working again.

Besides, you can also use a voltmeter or a multimeter to check the voltage or the resistance of the relay. Finally, if the relay is stuck open, it will most likely cause the starter motor to work even after the engine cranks. In this case, it could result in starter motor noises after the engine starts running, and the problem with fried solenoid or starter motor damage.

If the fuse itself isn’t the problem and replacing the fuse doesn’t work, the only thing you can do is replace the starter relay itself to fix the problem.

Our take

Ultimately, if there’s a blown starter relay fuse in your car, it will negatively affect the ability of your engine to even crank. If you don’t want to risk it and have the relay prevent proper engine starting, this guide hopefully provides all the details about the starter relay fuse.

So, replacing the blown fuse or changing the relay itself will once again make the starting system of your car work impeccably.