What Wires Go To The Starter Solenoid

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David Lawrence

This article is going to answer the following question in detail: ‘Diagram what wires go to the starter solenoid?’

Everything you need to know about how to wire a starter solenoid, from the basics, like its definition and principle, to the 4 pole starter solenoid wiring diagram, we have covered it all!

Looking for a reliable starter solenoid wiring diagram?

Let us get into it!

What Wires Go To The Starter Solenoid

A car’s engine is undoubtedly complex, and understanding it seems like a daunting task. The best way to go about it is to take one component at a time and understand it.

The starter solenoid is an incredibly important part of a car’s engine, which needs to be perfectly functional in order to ensure a smooth ride.

There are a lot of wires that go in and out of the solenoid, which makes it look so confusing. It can be best understood through a starter solenoid wiring diagram.

Are you on the hunt for a reliable 3 or 4 pole starter solenoid wiring diagram? Still, trying to figure out what wires go to the starter solenoid? This article has covered it all. Let us start with the basics.

Here it is broken down:


  1. The pin types ‘S’ terminal is the one that goes into the ignition switch
  2. Bolt-type feed terminal is the other one that connects to the battery positive power source
  3. Bolt-type output terminal is the last one that goes to the starter motor assembly,

Wiring Process of Solenoids

Credit – Toolsweek.com

Let’s dive into the nitty-gritty of a 4 pole starter solenoid wiring diagram! It may seem like a jumbled mess of connectors, but fear not – we’re here to break it down. Two of the terminals are responsible for high-current circuits, while the other two handle lower-current tasks.

These terminals are wired differently, with the high-current connectors leading to the power end and the smaller ones linked to the inner coil. In total, you’ll find four connectors in a solenoid, including two small ones for the switch and two thicker ones for those heavy-duty power needs.

To get started with your own wiring, make sure to connect the 12V battery using the black wire for negative and red for positive. And if you want to make things extra clear, try using orange and brown cables for your high-current circuits – they’ll definitely stand out!

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Defining Starter Solenoid

Let’s talk about what this component really is.

So, what exactly is a starter solenoid? It is an electromagnetic switch responsible for the battery’s connectivity to the starter motor assembly. It connects and disconnects the battery according to the need.

There is a bigger connectivity point in the starter solenoid in the form of a huge switch. It turns the starter motor assembly on and off. It should be noted that it works on the electromagnetic principle.

Starter Solenoid Functions

The functions of the starter solenoid are closely connected to what wires go to the starter solenoid, which is why we have discussed them in detail below. The vital engine component has mainly two functions:

  1. It controls the on and off start circuit, responsible for the connectivity between the batteries and the starter engine or motor.
  2. It also drives the starter pinion through the flywheel ring gear.

Let us look deeper into both functions before moving on to the starter solenoid wiring diagram.

Function 1

The starting of your car is no joke – and the solenoid is the unsung hero making it all happen!

When you turn on the ignition switch, the starter circuit kicks in, sending an electric current into the solenoid circuit. That’s when the magic happens – the solenoid switch sucks the movable iron core through electromagnetic force, bringing the two terminals together.

The first terminal connects to the battery’s positive pole, while the second terminal links up with the starter. It’s like a perfect dance between the solenoid and starter, all to get your engine purring.

So, nod to the mighty solenoid next time you turn the key!

Function 2

To understand the process of wiring a starter solenoid, knowing this function will help you understand it better. It can be better understood with the help of a starter solenoid wiring diagram which has been discussed in depth below.

So, the electric current stream gets divided into two while following through your starter solenoid:

  1. The first stream flows through the sucking coil, generating a magnetic force that sucks the movable iron core. This moves the fork backward for the starter pinion to engage the engine flywheel.
  2. Now, coming to the second stream. It flows through the holding coil, creating a magnetic force that keeps the core in the required post-pulling position until the start is complete.

Where is The Starter Solenoid?

The next step to understanding the process of wiring a starter solenoid is to know where it is located. This will also help you understand what wires go to the starter solenoid.

Your starter solenoid will most likely be mounted directly on top of your starter motor, which is quite easy to locate. 

The Starter Engine

Don’t get confused! Let’s clear the air on the starter motor and solenoid – two components often mistaken for each other.

The starter motor assembly is the beefy cylindrical part that cranks up your engine. In contrast, the smaller cylindrical starter solenoid (usually located at the top of the motor assembly) is responsible for connecting and disconnecting the battery and assembly.

So, what about those terminals? The small pin-type S terminal links to the ignition switch circuit and is sometimes called the starter solenoid control wire.

This wire powers up the solenoid by sending current through the fuse, neutral safety switch, starter relay, and finally into the starter solenoid.

On the other hand, the thick terminal is the input terminal. The battery positive power source enters the solenoid through this one, while the output terminal (connected to the starter motor assembly) is the second terminal.

Remember, don’t confuse the two – starter motor and solenoid are a team!

3 and 4 Pole Starter Solenoid Wiring Diagram

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Let us now get into the starter solenoid wiring diagram. Get ready to learn about the two types of starter solenoids: the 3 pole and 4 pole wiring diagrams.

Let’s dive into the juicy details! First, the 3 pole starter solenoid is your classic go-to starter solenoid. With three terminals at the back of the cap in the solenoid (one small and two thicker terminals), it’s also known as a 3 terminal starter solenoid.

Now, let’s move on to the 4 pole starter solenoid wiring diagram. Here’s the scoop: one of the larger terminals connects to the battery wire, while the second larger terminal connects to the starter.

As for the two smaller terminals, the first (S) links up with the ignition switch, while the second connects to either the ballast resistor ‘R’ or ignition coil ‘I’ (but is often left unused). Oh, and don’t forget to make sure the frame is grounded!

Starter Solenoid Problems

Now that we have discussed the diagram of what wires go to the starter solenoid, we can move on to common starter solenoid problems. If you want to wire a starter solenoid, being acquainted with the common issues can significantly help.

Following are the four of the most common starter solenoid problems:

  1. Suction failure during engine warm-up
  2. No chance of resting the starter solenoid during ignition
  3. The weakened elastic force of the return spring due to prolonged use
  4. Starter solenoid noise without engine rotation during start-up

Don’t worry, this guide isn’t exclusive to one car brand. It applies to all the big hitters – Ford, Chevy, Kia, Honda, Hyundai, Toyota, and beyond. So, buckle up and get ready to troubleshoot like a pro!

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where the wires go on a starter solenoid

Below is the frequently asked question on where the wires go on a starter solenoid. Let’s dig deep to know more.

Does it matter which wire goes where on a solenoid?

No. Because polarity does not matter on solenoid valve coils. Generally, the lead wires will have the same color so that you can connect the positive terminal to either of the two wires.

What are the two wires to the starter solenoid?

A starter solenoid has a small connector for the starter control and two large terminals. These two large terminals are for the positive battery cable and the wire that ignites the starter motor.

What is the small terminal on a starter solenoid?

The small terminal is essential for the starter control wire that connects to the ignition switch.

Can you wire a solenoid wrong?

The thing is, DC solenoids have polarity if you are using a couple of deprived wires as your connector instead a real connector with the ability to guarantee the correct connection. Suppose you have a 50-50 chance of getting the polarity wrong.


That was all I wanted to say on what wires go to the starter solenoid. Understanding what wires go to the starter solenoid is not that hard. A starter solenoid wiring diagram is the best way to understand it. If you want to wire a starter solenoid, a detailed 3 or 4 pole starter solenoid wiring diagram can also be handy. It is important to remember that having basic information about one’s engine is helpful in emergencies. It is better to take these precautions!

Hey there, thanks for sticking around until the end. I’d love to hear your thoughts and feedback, so don’t hesitate to share them with me! Wishing you a beautiful day filled with peace and positivity.

Catch you on the flip side!

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David Lawrence

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