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How to Test a 5 Pin Relay with a Multimeter (Guide)

At times, you might want to check whether a 5 pin relay is working correctly, there could be many reasons for this including diagnosing electrical issues and maintenance. Most people do not know how to test a 5 pin relay or even where to begin.

You can easily check a 5 pin relay with a multimeter through these easy-to-do steps.

  1. Test the relay’s coil.
  2. Test the relay’s terminal.
  3. Test the normally open terminal.
  4. Test the normally closed terminals.
  5. Test the common terminals.

Before diving into the main topic, let’s get a basic understanding of what a relay and multimeter are.

Do All Relays Test the Same?

A relay is a switch that assists in opening and closing circuits electronically. These switches use a small amount of current to control bigger and larger currents. Now for 5 pin relays, the difference is they can provide 2 pins to control coins and then have 3 pins that are created to switch the power between circuits.

power switch - on and off

How to Check 5 Pin Relay with a Multimeter

mechanic testing car engine with multimeter

Relays are important devices and fragile devices. Due to this, they can become faulty and need regular relay tests to ensure they are in good working order.

A 5 pin relay is made up of 2 pins that control the coil. Three pins switch power between the circuits. The three pins have normally open (NO) and normally closed (NC) connection pins.

When power is supplied to the coil, the three other pins switch the current, and normally closed pins become normally open pins.

Testing the Relay’s Coil

In this first step, we will measure the resistance passing through the relay. You will be required to connect the multimeter in the resistance measurement mode and the dial knob in the 200Ω knob.

Since resistance is not affected by polarity, it doesn’t matter where which pin is connected to on the input jack.

Then, take the two lead probes and place them across the coil terminals for the relay. If the relay is in good working order, the multimeter will record a reading depending on the range of the datasheet. (1)

If it does not show any charge, the relay test has failed and it should be replaced immediately. Since a coil is non-repairable, you will need to change it.

yellow color multimeter

Testing the Relay’s Terminal

For this next step, you will need to connect the digital multimeter in continuity mode. This is so that you can measure the continuity of the terminals of the multimeter.

Normally, there is very little resistance between the two terminals of the relay. Place the two lead probes on the contacts of the relay.  If a high resistance reading is recorded on the LCD of the multimeter, this shows that the two terminals are not connected to each other. The reason for this will be that the terminals are connected together by a coil. If it is faulty, you will have to replace the relay with one that is working.

It’s now time to examine the relay’s numerous terminals. The best method is to measure the resistance between terminals. I’ll show you how to test the items below:

  • Normally open terminal
  • Normally closed terminal
  • Common terminal

Testing the Normally Open Terminal

When testing the normally open terminal, the digital multimeter will remain connected the same as the first step. The resistance of the terminal will tell you if they need changing.

Place one of the lead probes on the open terminal and the other probe on the COM terminal of the relay.  It doesn’t matter where each lead probe goes into which jack input.

Then read the resistance in the LCD screen, if it is around several milliohms, then the relay is working fine. If you get a higher reading of resistance from the multimeter, the relay is working fine also. A reading of zero on the LCD screen will indicate that the relay terminal is faulty and needs changing.

technician testing with multimeter

Testing the Normally Closed Terminals

The multimeter should still be in the resistance setting. Place one of the lead probes on the COM terminal and the other on the normally closed terminal. Then read the resistance on the screen. If it reads resistance of close to zero ohms, then the relay is working well and should not be changed. If there is a reading of very high resistance, this means the normally closed terminal is faulty.

Testing the Common Terminals

With the multimeter still on the resistance setting, place the two lead probes on the 2 terminals of the relay’s coils. (2)

If you read a very high or very low resistance, this means the relay is not working properly and should be changed immediately; if the read value is a rated resistance, then the relay works fine.

Wrapping Up

Using a multimeter to do a 5 pin relay test saves time and also helps you avoid further damage to your equipment. A 5 pin relay can be tested with a multimeter and how you can use it whenever the need arises. I hope this article will be beneficial to you and help you fix that relay.

You may want to bookmark other testing guide’s we’ve written below.

(1) datasheet – https://www.sciencedirect.com/topics/
(2) coils – https://www.britannica.com/technology/coil

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About Sam Orlovsky

AvatarCertifications: B.E.E.
Education: University Of Denver - Electric Engineering
Lives In: Denver Colorado

Electrical engineering is my passion, and I’ve been in the industry for over 20 years. This gives me a unique ability to give you expert home improvement and DIY recommendations. I’m not only an electrician, but I also like machinery and anything to do with carpentry. One of my career paths started as a general handyman, so I also have a lot of experience with home improvement I love to share.

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