How to check fuses with a multimeter

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How to check if a fuse is bad?
How to check the fuse and relay with a multimeter?
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Below I will teach you how to test a fuse with a multimeter. You also need to look inside the fuse to really get to the bottom of things and see if it's blown. I will teach you how to do both below.

Important steps we will go through:

Given the voltage of the fuse.
Ohm measurement
Checking the fuses in the fuse box
Fuse blown resistance measurement
Checking the current state of circuits

If you have a reading between 0 - 5 ohms (ohms), the fuse is good. Any higher value means a bad or defective fuse. if you read OL (over limit) it definitely means a blown fuse.

How to check with a multimeter if the fuse is blown?

In this case, checking whether fuse blown by eye test just might not be enough. Therefore, you should use a multimeter to eliminate all doubt.

Your best bet is to do an electrical test and check what's wrong with the fuse.

First of all, you must have continuity mode on your multimeter. Most of the best multimeters now have this mode of use. Then one of the probes must be placed on one end of the fuse. Of course, the other probe of your multimeter must also be placed on the other end of the same fuse.
Here the main goal is to determine if the fuse is good. Thus, in continuous mode, the multimeter should beep to indicate continuity.
If you can check for continuity, the fuse is not blown. In other words, this means that no connection is corrupted or dropped.
On the contrary, it may happen that the multimeter shows a high level of resistance without sound. So, when this happens, the main reason is that the fuse has already blown and is therefore useless.
You can also use a multimeter ohmmeter if it doesn't have a continuity mode. So, you have to choose an ohmmeter and put each waveform on each end of the fuse.
If the fuse is intact, the ohmmeter reading should be low. Conversely, readings will be very high if the fuse is damaged or blown. (The fuse is good if its reading is between 0 and 5 ohms (Ω).. Any higher value means a bad or defective fuse. If your reading is OL (Over the Limit), which means a blown fuse.)

How to check if a fuse is bad?

This is where checking the health of the fuse will allow you to avoid many common unforeseen circumstances. However, a good fuse is not always available, so you should learn how to check the condition of the fuse. You can use a multimeter or you can immediately determine if the fuse is completely blown.

Finding a blown fuse is not very difficult. Sometimes the main fuse connector melts or breaks.

If you cannot guarantee this, you may continue to use the multimeter. Usually, when a blown fuse has a broken connector, there is nothing left to do but fix it. Conversely, the fuse is OK if the internal connector is not melted. This connector must be in good condition from one side of the fuse to the other.

Obviously it would be better if you had a new fuse to replace the blown one. Of course, there are many fuses available on the market. So you also have to make sure that the new fuse is the same type as the old one.

How to check the fuse and relay with a multimeter?

To test a fuse with a multimeter, you must use the continuity mode on the multimeter.
It would be better if you connected multimeter leads to each end of the fuse. If you can determine continuity on a multimeter, the fuse is good. Conversely, it's a blown fuse unless you find continuity in your multimeter.
On the other hand, you can check whether the coil relay is in good condition or not. It would be better if you also had a digital multimeter with seven functions for this.
In this case, it is necessary to use resistance mode between each pole of the relay. Here the reading should be zero in the corresponding pole of all contacts. (1)
At the same time, the contacts in this area should also be treated as an infinite resistance reading if you place the probes on the appropriate pole. Then you can continue after turning on the relay. You will hear a click when the relay is energized.
You will then have to repeat the procedure with a multimeter. Here, the resistance of the opening and closing contacts must be adequate. You can also test solid state relays with a multimeter. (2)
In this case, you need to have a diode reading to test this type of relay. The multimeter will show the voltage applied to the relay. The counter will show zero or OL when the relay is not working.
Conversely, a relay in good condition should give a result of 0.5 or 0.7, depending on the type of relay.
Solid state relays are usually cheaper and easier to repair.

We have other HOW-TO articles that you can check out and bookmark for future reference. Here are some of them: "How to tune an amplifier with a multimeter" and "How to use a multimeter to check the voltage of live wires." We hope this tutorial will help you.