How To Tell If Starter Relay Or Solenoid Is Bad? | Car Problems and DIY Solutions

Imagine taking a seat in your vehicle. For your safety, fasten your seatbelts. Nothing happens when you start the car and turn the key in the ignition. There was nothing but a click. Your automobile won’t start because the engine won’t turn over.

The battery may be dead. However, given that the dash lights, radio, and headlamps all appear to be operational, it’s possible that something else is to blame. This could indicate that your car’s starter relay – also known as the starter solenoid – has failed.

What Exactly Is a Relay?

You’ve heard of this word if you work in the electronics sector, but if you haven’t, let us fill you in!

Relays are electronic and electromechanical switches that close and open circuits. It controls how an electrical circuit’s circuit connections open and close. When the relay contact is open, the relay is not activated by the open contact (NO). Due to the closed contact, the relay is not powered if it is closed (NC). The states are more prone to change when energy (electricity or charge) is supplied.

What exactly is a solenoid?

A solenoid is a device that consists of a wire coil, a casing, and a movable plunger (armature). A magnetic field forms around the coil when an electrical current is introduced, drawing the plunger in. In another way, a solenoid turns electrical energy into mechanical work.

Solenoid vs Relay

The ignition switch is activated when you turn the key to start your car. Like the majority of the switches in your car, the ignition switch is made of plastic and controls a low-powered signal, in this case, to start the engine.

The signal is an electrical current in earlier vehicles (like a light switch in your house) and an electronic impulse delivered to the vehicle’s computer in later vehicles. The switch, in any case, “tells” the starter circuit to engage.

However, the starter itself necessitates a significant amount of power. Certainly more than the ignition switch’s teeny-tiny wires can manage. The starter’s job is to turn the engine’s internal elements, which necessitates a lot of torque and hence greater power. As a result, automakers include a technology that allows a low-power signal to activate a high-power signal. A little switch can thus enable a large task (such as starting an engine).

A relay and a solenoid are both devices that use a low-power signal to close (or sometimes open) a much bigger, more powerful circuit. The ignition switch (possibly via a computer) informs the relay/solenoid to activate the starter and the starting circuit’s relay/solenoid switches.

The phrases relay and solenoid are now frequently used interchangeably, causing a great deal of confusion. (We hope that we don’t add to the uncertainty.) A relay and a solenoid are both remote electromagnetic “switches,” however they are built and operated differently. Both can control a high-power signal with a low-power signal, and they can do it in the same way.

As a result, the terms are commonly used interchangeably. Because of its construction and operation, a solenoid can normally switch a larger current than a relay.

These devices are situated in different car areas, thus muddying the waters. In some cases, a relay and a solenoid are used in the ignition system. In that situation, the solenoid will be triggered by the relay.

A real starter relay is typically a little black cube hooked into an electrical fuse/relay box engine compartment. In contrast, a starter solenoid is (in most cases) attached directly to the engine’s starter (although it is sometimes located elsewhere in the engine compartment).

Signs of a defective starter solenoid

Because difficulties with the starter solenoid are more common than problems with the plug-in relay, we’ll concentrate on symptoms linked to the solenoid. When you turn the key, look for these possible indicators of a failed or damaged starter solenoid:

If you turn the key in the ignition, there may be various issues, but nothing happens. The solenoid is one alternative.

A single “click” sound can be heard from the engine compartment or below the vehicle. This could mean that the solenoid is attempting to engage but cannot do so due to stuck internal components.
Repeated “clicking” sounds frequently indicate a dead battery. However, a malfunctioning solenoid that fails to establish appropriate electrical contact inside can cause the battery to have low voltage, preventing it from providing enough power to start your engine.

Instead of preventing the engine from starting, a malfunctioning starter solenoid may cause it to start on its own even if the key is not in the “start” position.” This less-common problem is potentially dangerous and should be addressed soon.

If the starter activates but does not disengage when the key is removed, the solenoid is faulty, and the starter could be severely damaged.
Your automobile will start sometimes, but not all of the time. A faulty starter solenoid might cause intermittent operation.