4 Pole Starter Solenoid Wiring Diagram-You Need To Know

A starter solenoid is a type of electromagnetic switch. The main purpose of it is to keep the ignition switch away from the high amperes required for the starter motor. Most heavy-duty starter solenoids have 4 poles from where wires can go to.

Likewise, a starter solenoid can be difficult to wire, considering its complicated function of starting a motor for the combustion engine. It might also be known as a starter relay, but not always.

How Does A Starter Solenoid Work?

Starter Solenoid 4 pole Working Function

In short, when you insert your key inside the ignition to start up your car, it first goes through the starter solenoid from the ignition switch. From there, it loses two heavy metal contacts.

These can relay a lot of energy, to the starter motor, but it makes sure to isolate the ignition switch first. Then the starter motor can start the engine and set it in motion.

After that, the solenoid works with a part called the “plunger”, which is a lever. This forces the “pinion” to the ring gear and locks them together. This is important as the ring gear can clutch your engine and essentially stops the starter motor from spinning so fast that it’s dangerous.

These are the technical terms for how a solenoid works when you switch the key in your ignition switch. But in simpler terms, you first get energy from the starter solenoid to the starter motor, and that activates several parts to work with each other and make your engine run smoothly.

The 4 Pole Starter Solenoid Wiring Diagram & How to Wire It

To get a hold of the wiring, 4 pole starter solenoid wiring diagrams are a must. And here is one-

4 Pole Starter Solenoid Wiring Diagram

Source: Daniel Martin

In this diagram, there are two colors to make it easier to understand. As most of the time, they’re color coded and you can tell which wire goes where, you can wire it easily by following this diagram.

But before we dive into details, you should first learn color coding to get a better idea of how to wire them. The most common color coding is listed below-

Pole 1Red
Pole 2Black
Pole 3Blue With Red Stripes
Pole 4Brown

This color coding isn’t universal, but it’s still the most common color coding system and you’ll see it often when wiring a 4 pole solenoid.

Now, it’s time to know how to wire a 4 pole starter solenoid.

The “3)” is the starter solenoid, and as you can see, it has 4 poles. Here is the name of all the parts with their numbers —

  1. Starter motor
  2. Engine ground
  3. 4 Pole Starter Solenoid
  4. Ignition Switch From Key
  5. Battery
  6. CDI
  7. Coil
  8. Frame Ground
  9. Kill Switch

The solenoid goes to the starter motor, engine ground, kill switch, coil, and frame ground on the right side poles. And on the left side, it goes to the ignition switch and the battery. That’s about all for the wiring from all 4 poles, and usually, it’s color coded.

Since it’s a 2d diagram, the color coding isn’t shown properly, but it’s mostly color coded. It can be slightly different, but the colors are generally red, black, blue with red stripes, and brown for poles 1-4. Thus, the colors might be different for different vehicles, so always check the instructions.

Moreover, you can check this YouTube video by RattyMuscleCaror for a more detailed video explanation.

Things to Keep In Mind When Wiring A 4 Pole Starter Solenoid

Starter Solenoid 4 pole Wiring Process

Wiring can be quite challenging, so here are a few things that you should keep in mind when wiring a 4-pole starter solenoid —

  1. Make sure that your solenoid is properly grounded, or else it might lead to issues. The brackets beside the coil act as the ground, so make sure they’re mounted properly.
  2. You need to make sure that the battery and other power connections are connected to the terminal which is in the same direction as the original terminal.
  3. For wiring the starter terminal, you should go in the opposite direction of the original terminal.
  4. The starter terminal is the one that connects to the ignition switch, so make sure you connect it properly.

What Are The Different Starter Solenoid Terminals?

Starter Solenoid 4 pole Terminals

When wiring, it’s important to know the different terms for the solenoid terminals. They’re shown below-

  1. Terminal S, also referred to as 50 is the most important terminal, and it’s known as the starter terminal. It’s for the control wire and connects to the ignition switch with the starter relay.
  2. Terminal B, referred to as 30, often is used for the battery cable on the positive side.
  3. Terminal C, also known as terminal M is for connecting the S terminal to the starter motor.

These are all the common terminals. You might also have a 4th terminal called Terminal R or I connecting to the ballast resistor and ignition coil, but it’s rather uncommon.


Q: Can the wiring function when you use the wrong wire?

No. As we know, most of the time a 4 pole solenoid starter is color-coded. But if you use the wrong color for the wrong pole, it won’t work. So make sure to properly check the wires and the colors before finishing the wiring.

Q: What are the wires that connect to the starter solenoid?

The wires that connect to the starter solenoid are the starter control wire, the battery cable on the positive side, and the thick wires for the starter motor.


A detailed 4 pole starter solenoid wiring diagram can help you understand how to wire it better. But for more help, you should know which wire goes where as well as the color coding. This way, it almost becomes intuitive to wire all the complicated parts together.

Nevertheless, you won’t always need to wire it yourself. So if you don’t want to go through the bother of wiring everything, you can just call up a local automotive store and they can do it for you. Generally, they don’t charge much either. Cheers!

Mark Williams

Leave a Reply

Your email address will not be published. Required fields are marked *