How to Test a 5 Pin Relay With a Multimeter (With Pictures)

How to Test a 5 Pin Relay With a Multimeter

Testing a 5-pin relay with a multimeter is an important step for anyone who works on electronics or electrical systems. It is essential to ensure that these relays are functioning properly and up to the desired standard. Knowing how to test a 5-pin relay can be intimidating for those without any prior experience, but this article will simplify the process and provide clear instructions.

A relay is like a switch that helps power to flow in certain directions. The 5-pin relay is a type of electrical device used to flow the current and voltage in a circuit. It is an important piece of equipment that can help regulate the power supply in a variety of applications. Testing a 5-pin relay is not difficult, but it does require the right tools, including a multimeter. In this article, we will explain how to properly use your multimeter to test a 5-pin relay and ensure it is functioning as expected.

How Car Relay Works

Before we start testing the five-pin relay. It is important to know how a car relay works. Consider a relay as two halves. One circuit is known as the Coil circuit (also called a low voltage circuit, a low amperage circuit, controlling circuit. The second half circuit is called a load circuit or high amperage circuit.

Keep in mind that the load circuit is controlled by the coil circuit. When a current is applied to the relay’s coil circuit, a magnetic field is created that attracts the movable rod and establishes a physical connection between the high-amperage circuit.

On the other hand, if the electric current is removed from the coil circuit, the movable bar will return to its original resting location, enabling it to disconnect the high-amperage circuit.

Related Post: Car Relay Guide: What it is & How A 12V Relay Works

How to Test a 5 Pin Relay With a Multimeter

5 Pin Relay Diagram
5 Pin Relay Diagram

A relay has two circuits, a coil circuit, and high amperage circuit. The coil circuit has two terminals called 85 and 86 terminals, where terminal 85 is designated as a negative terminal and is given ground power, whereas terminal 86 is designated as a positive terminal and is given a hot power source. The coil circuit is the circuit when you pass the power, you hear a clicking noise.

High amperage circuits have three terminals called 30, 87, and 87a, in which terminal 30 is a common terminal and terminal 87 is a power-out terminal, indicating that the 12-volt supply exits from the relay to the component. There is also a third terminal 87a which plugs into the five-pin relay. This terminal is required when power is not required while simultaneously energizing the relay, and by energizing the relay, power is cut.

Five Pin Relay Terminals
Five Pin Relay Terminals

As the name implies, the five-pin relay has five pins. Two pins control the coil, and the other three help switch power from one circuit to the other. The relay can be tested using a multimeter to measure voltage, resistance, and electric current.

We will divide the five-pin relay into two categories (Coil circuit and High Amperage circuit) and will test both categories. Below we will cover the basic steps that must be taken to accurately and safely test a 5-pin relay with a multimeter.

  • Testing Relay’s Coil Circuit
  • Testing Relay’s High Amperage Circuit

1. Testing Relay’s Coil Circuit With a Multimeter

Testing Five-Pin Relay's Coil Circuit
Testing Five-Pin Relay’s Coil Circuit

The relay’s coil circuit contains pins 85 and 86, which are the two pins on the sides. The first step involves testing the resistance flowing through the coil’s circuit relay. You will have to switch the multimeter to resistance measurement mode.

Five-Pin Relay's Coil Circuit
Five-Pin Relay’s Coil Circuit (Source: Youtube)
  • Connect the two leads to the multimeter. Note that the polarity does not have any effect on the resistance. It allows you to connect the input jack to any pin.
  • Once the leads have been connected, observe the multimeter screen. The resistance of the circuit’s coil is approximately 50 to 120 ohms. If the reading is within the specifics of the mentioned figures, the coil is working fine. However, the coil is faulty if the reading is not within the specifics of the mentioned figures, which could be either high or low. At this point, you will have to replace the coil.

2. Testing Relay’s High Amperage Circuit With a Multimeter

The next step is testing the relay’s high amperage circuit. The high amperage circuit contains three pins 30, 87, and 87a. We will test pins 87 and 87a with respect to pin 30. For this, you will have to switch the multimeter to resistance mode. Continuity mode testing also involves checking the terminal to confirm if it is open or closed. The best way is to test the resistance between the terminals. Below is how to carry out the tests. 

  • Testing Pins 30 and 87
  • Testing Pins 30 and 87a

Caution: Do not use an ohmmeter to measure ohms while communicating with a live wire. The volts can harm the ohmmeter while studying the resistor while a current is flowing. Here, I’m referring to the amperage circuit of the relay. Do not use an ohmmeter when the high amperage circuit is connected to the source of the power.

A. Testing Pins 30 and 87 Of Five-Pin Relay

Testing The High Amperage Circuit Of Five-Pin Relay's Terminal 30 And 87
Testing The High Amperage Circuit Of Five-Pin Relay’s Terminal 30 And 87
  • To test pins 30 and 87, first, ensure that the multimeter is switched to resistance mode. Connect the multimeter’s red lead to pin 30 and the black lead to pin 87 (Pin 87 is also called a normally open terminal).
Testing Five-Pin Relay's Terminal 30 And 87
Testing Five-Pin Relay’s Terminal 30 And 87 (Source: Youtube)
  • Now, energize the relay by giving power to the relay’s coil circuit. When the relay is energized, pins 30 and 87 will start to have continuity. While testing, if the ohmmeter reading is too low or close to zero, then the pins are working properly. If the ohmmeter checks for resistance on the pins 30 and 87 circuits by its abbreviation, OL, which means that Open-Loop or Open Load or with very high resistance. It means that the circuit is open and does not have connectivity, which indicates the relay is faulty.
  • You can also test pins 30 and 87 by using continuity mode in the multimeter. The continuity mode of the multimeter also emits a beep when a closed circuit is detected, indicating that the continuity of test leads has been established.

B. Testing Pins 30 and 87a Of Five-Pin Relay

Testing The High Amperage Circuit Of Five-Pin Relay's Terminal 30 And 87a
Testing The High Amperage Circuit Of Five-Pin Relay’s Terminal 30 And 87a

We will test pins 30 and 87a. Pin 87a is also regarded as a normally closed terminal. To test normally closed terminals, ensure the multimeter is switched to resistance. Proceed to connect the red lead to pin 30 and the other black lead end to be connected to pin 87a.

  • As pin 87a is normally a closed terminal, therefore, pins 30 and 87a will have continuity before energizing the relay and the multimeter will read zero ohms or close to zero. However, if by energizing the relay, the circuit between pin 30 and 87a is still intact, the relay is faulty. It should be disconnected by energizing the relay.
  • Now, energize the relay, the continuity between pins 30 and 87a will break and the circuit continuity will shift between pins 30 and 87. If the multimeter reads zero or close to zero ohms by testing pins 30 and 87, then the relay is working fine. However, if the ohmmeter reading shows an OL circuit. This means that the circuit is open and there is no connection, indicating a faulty relay. Continuity mode in the multimeter also emits a beep when it detects a closed circuit, indicating that there is continuity between the test leads.

Final Thought

Testing a 5-pin relay with a multimeter is a simple process that is not too much time-consuming or difficult. You must first identify the pins and their corresponding functions in order to properly assess the relay. After you have done this, you can begin testing your relay by setting your multimeter to ohms and measuring the resistance between each of the pins. If you do find any issues with the relay, replacing it may be necessary depending on its function and importance in the circuit. Bear in mind that you must not fix a damaged relay. 

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