Bad Fusible Link Symptoms: with Diagnosed and Replace Solution

How do you determine whether the problems you are facing come from a bad fusible link or a problematic ECU? It is very hard to tell. Because the symptoms you will see are a lot similar in both of them. But when you can replace the fusible link by spending only a couple of bucks, you are going to need a lot more than that to fix any ECU-related problems.

replace fusible link with fuse

That’s where the real problem is. In this article, I am going to state the symptoms of a bad fusible link with specific details. And I hope it will make your life easier to find out the main issue behind your vehicle’s electrical problems.

What is a fusible link used for

Let’s start with the basics. Why do we use a fusible link in a vehicle? “Fuseable Link” and “Fusable link” are the other names of it. The name kind of says us the work it does. Yes, its function is a lot like electrical fuses.

In any electrical device, we use a fuse to protect the other components of the device. Basically, the fuse uses a kind of material in the wire that can melt easily. And in case of an overflow of current, the fuse will get melted and break the circuit to protect the rest of the wiring.

Similar to these electrical fuses, fusible links (insulated low-voltage cable) also protect the rest of the wiring by getting melted in case of an overflow of current. And that makes sure that the components of your vehicle stay safe.

Note:18 gauge fusible links are rated at 14 gauge wire or 15 amps, 16 gauge are rated at 12 gauge wire or 20 amps.

fusible link color chart
Fusible link color chart

What Is Fusible Link | What’s Fusible Link Used For

Fusible link problems

What does it mean by fusible link problems? It means either the problems you will face if the fusible link is blown up or the problems you will face if you do not replace the blown fusible link. In this section, we will state both of these stages’ problems.

Problems you will face right after the blow:

i. Failure of windows: One of the first things you will notice if your vehicle’s fusible link goes bad is that the opening and closing of windows won’t work. You won’t be able to do that automatically. You have to use a manual unlocking system in that case.

ii. Failure of central locking: Along with the failure of windows, you may not be able to use the central locking option too. And this is a situation where you need immediate remedy as security is the concern.

iii. Failure of wipers: Failure of wipers is another problem you will face if the fusible link goes bad. In that case, you will be blind to rains and snowfalls.

iv. Failure of radio: Do you love to tune your vehicle’s radio on a regular basis to enjoy your favorite RJ’s show? Or to hear the news update? In case of a blown fusible link, you may not be able to tune the radio too. v. Failure of Music: Who doesn’t love music during a long drive? Even in a shorter course, you would love to hear the top chart’s one or two. But you may fall into a problem hearing music in your vehicle if the fusible link is not in shape to do its job.

Problems you will face if you do not replace the blown fusible link:

The problems we stated above are the mere possible cases if the fusible link fails. You may face only one or two or even all of them at once. But if you try to continue driving your vehicle in this state by bypassing something, it won’t get started.

Why fusible links are there in the first place? To protect the components of your vehicle, right? And what will happen if this is not there to do its job? There won’t be anything to protect the electrical components of your vehicle.

But you don’t need to worry about this much. Because the vehicle won’t even start to cause those hypothetical problems. However, you need your vehicle to start, don’t you? That is why you need to replace the blown or failed fusible link as soon as possible.

A blown fusible link is identified by

You may get an idea about a blown or a bad fusible link by the symptoms. You will see one or several symptoms if the fusible link gets blown. But you have to inspect the fusible link to make sure it is really the fusible link problem. The symptoms are-

1. Problem in the central locking

2. Issues with the windows

3. Issues with the wipers

4. Music and radio failure

The confirmation of the fusible link problem is very necessary. You don’t want to configure the starter motor or ECU for a bad fusible link, do you? No, you don’t. First, it won’t solve the starting problem. And second, it will cost you much more than the replacement of the fusible link. Okay, how do you diagnose or inspect the bad fusible link? Let’s get to that part.

Diagnosis of a bad fusible link

This process is pretty simple. At first, you have to go under the hood. Afterward, you have to find the battery. The fusible link usually resides near the battery. Search for a wire that is two gauges roughly smaller than other harnesses. If you touch the wire, you may feel it is even more rubbery than the other wires.

And there may even be “fusible link” printed on the wire. If you can find the writing, it is easy as a piece of cake! After you find the fusible link, watch out for any blow or damage in the wire. Then you will know what happened.

The fusible link between alternator and battery

In the early days, more precisely- before the 1980s, you would not find any fusible link between the alternator and the battery. But the trend got changed. Well, it was all for security purposes. After the 1980s, engineers started using the fusible link between a battery and an alternator.

They did it to prevent any fire or damage in between the alternator and battery. For instance, someone may install the battery with reversed polarity or diode in the alternator gets failed. In that case, there will be damage between the alternator and the battery. That is why it is necessary nowadays to place a fusible link between the alternator and the battery.

How do you know if your alternator pulley is bad? How do you check an alternator clutch pulley? What is the purpose of a clutch pulley on an alternator?

How to replace fusible links?

The first thing you need to do is to diagnose or inspect the fusible link. After the inspection and identification, you are ready to go. Now you have to follow the following process-

  • First, remove the existing blown fusible link.
  • Second, place the new fusible link in the place of the old one.
  • Lastly, make sure you use the right fusible link (which has more resistance than the wiring)

Using a fuse instead of a fusible link may be a tempting idea. But you should not do this. Engineers made the fusible links for a reason. You must trust them in this regard. Because if it would be okay, they would use fuses instead of fusible links in the first place.

Note:Choose the fuse according to the wire size

Replace fusible links with fuse

Well, the first thing we would tell you that it is a very bad idea. You should not go for this if you are not in a dire situation. Although the job of both these wires is the same, it is not ideal to replace a fusible link with a fuse. Generally, a fusible link is a compact wire and can handle a huge amount of current before getting blown.

On the other hand, fuses can’t do the same. The common fuses can’t serve the purpose of a fusible link. But if you want to replace a fusible link with a fuse anyway, you should go for mega fuses. Because the smaller ones are likely to handle only about 50 amps that can’t do the job as a replacement by any means.

Nissan fusible link replacement

Fusible link replacement is not a hard process at all, we know that. Almost all the cars have fusible links in a selected area. That is why it is very easy to find and remove the fusible link without much hassle.

But in order to replace a fusible link in a Nissan car, you might have to struggle a little bit. In the older models, you would have to remove the fuse box altogether to replace the fusible link. And if you don’t know what you are going to do, we always suggest going to an expert.

Nissan fusible link Failure, main battery cable fuse

GM fusible link

The popular brand GM has a fusible link that goes by their name. And for this product, you won’t need to pay more than $3. This is a 14 gauge and 9.5 inches long fusible link. And the stud size of this one is 3/8 inches. If you want to replace the fusible links of GM Motor’s vehicles, it is always an ideal choice to go for this product.

Fusible link chart

Fusible link chart

How do you size a fusible link?

4-gauge wire Protected by18-gauge fusible link
6-gauge wire Protected by10-gauge wire fusible link.
10 gauge wire Protected by14 -gauge wire fusible link.

NOTE: The fusible link that protects the wire should be two gauge sizes (or four numbers larger). The length of a fusible link should not exceed 9″ .19, 15, 13, and 11 are counted when sizing a link


What happens when a fusible link goes bad?

You will start seeing symptoms if that happens. Although the ignition will remain safe, you will face issues with the electrical components. As the fusible link has gone bad and broken the circuit, there won’t be any flow of current and the vehicle won’t start. Don’t get confused with this problem with the starting motor issue.

How do you tell if a fusible link is bad?

As the symptoms are quite similar to starting motor problems and ECU-related issues, it is really hard to tell. If you see the symptoms, you have no way but to go under the hood. Near the battery, you are most likely to find the fusible link. If you see it, you will know the condition of it.

Can you replace a fusible link with a fuse?

Technically, yes. But it is not a good idea. The vehicle engineers had put the fusible links in the vehicles in the first place for a reason. Fusible links are compact in structure and able to handle a lot more current than the common fuses. But if it is urgent or you want to do it anyway, we recommend you using mega fuses to get the job done.

What does the fusible link do?

The job of a fusible link is to provide safety and protection to the components. The fusible link does it by breaking the circuit in case of an overflow of current. You can say the function is more or less like the function of electrical fuses.

How long are the fusible links?

Well, there is no definite length of a fusible link. The length depends on the wire size of the conductor. Generally, the wire size of the fusible link is 4 gauges smaller than that of the original conductor. Plus, you should not use fusible links that are longer than 12 inches.

How do you test a fusible link alternator?

In this case, to test a fusible link near the alternator, you have to use a voltmeter or a multimeter. Use the meter in the wiring of the fusible link. By seeing the result, you will know what happened there.

Alternator problems? Do a Fusible links test


A fusible link is a tiny piece of wire that makes sure your vehicle’s other electrical components stay safe from any possible overflow of current. That is why it is very important to keep the fusible links updated. Well, in case you don’t do that, you won’t be able to start the vehicle.

The symptoms you will see are very similar to the problems regarding starting motor and ECU-related problems. It is very much possible to get confused. And thus it is too important to confirm that it is a fusible link problem first. Otherwise, you are nothing but wasting money. And hey, do not forget to let us know your thought in the comment box. If you have any queries, you are welcome.

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