How to reset an aftermarket car alarm


Last updated on March 4th, 2023

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While aftermarket car alarm systems can be excellent theft deterrents, they can sometimes prevent you from entering and starting your own vehicle. Whether due to a faulty alarm system or because you lost your key fob, in this article, we are going to teach you how to reset your aftermarket car alarm system.

So, if you are locked out of your car or if you need to reset the alarm for other reasons, do not worry. We’ve got you covered.

how to reset an aftermarket car alarm

Why choose an aftermarket car alarm over the factory one

Not every aftermarket car alarm system is a direct upgrade to the stock alarm system of a vehicle. However, high-end aftermarket systems offer so many good features that they should at least be worthy of your consideration.

With a good aftermarket car alarm system, you have access to plenty of security features that stock vehicles usually do not come with. Here are some of the features that are a direct upgrade over most stock alarm systems:

  • Sensitivity – high-end aftermarket car alarm systems are more sensitive than the stock alarm system of your vehicle. The smallest bumps will trigger good aftermarket alarms, letting you know that somebody might be trying to hijack your vehicle.
  • Anti-hijacking features – most aftermarket alarm systems prevent starting the vehicle without disabling the alarm first.
  • Fob range – the range of an aftermarket system fob is noticeably longer than the stock option. This allows you to start your vehicle from a considerable distance.
  • GPS tracking – In the event your vehicle gets stolen, advanced alarm systems allow you to track your vehicle.

Why do you need to reset an aftermarket car alarm?

Although aftermarket car alarms are usually better than stock options, they are also more prone to having problems. Luckily, most of these problems can be easily fixed with a reset.

Resetting the alarm is also useful if you lose your key fob. If you lose access to the normal method of disabling your alarm, you may experience difficulties starting your vehicle. By resetting the alarm, you are able to bypass the problem and get your vehicle started.

How to reset an aftermarket car alarm

Aftermarket car alarm systems are usually disabled by the key fob. However, a dead key fob battery (or the loss of the key fob itself) might prevent you from disabling your alarm and starting your vehicle.

In that case, you might need to reset your aftermarket car alarm. But how exactly do you do it?

Using the valet switch

While this feature isn’t present in every aftermarket car alarm system, some systems have a valet switch that automatically disables most alarm functions of the vehicle. While it might seem counterproductive, this feature was designed so vehicle owners didn’t have to hand their alarm key fob to mechanics and valets.

If you can get your car doors open, then hitting this switch might be enough to disable and reset your aftermarket car alarm system. If you are unable to unlock the doors, then you need to try an alternative method, such as:   

Disconnecting the battery

If the car alarm has no power, then it can’t run. However, once the power is back on, the alarm will probably fire again. If you just want to get the doors open, then it shouldn’t be a problem. But if you want to start the car, you will need to connect the battery again, which will probably trigger the alarm. So, how do you fix this?

First, you need to disconnect the battery. Just pop open the hood and disconnect the negative terminal. Then, with the hood still open, you need to manually hold down the hood position detector (a small switch located on the hood) and reconnect the battery. If done correctly, the alarm shouldn’t be triggered anymore.

You need to hold the hood position detector switch because otherwise, when you reconnect the battery, the alarm system will think the vehicle is being tampered with. If it thinks the vehicle is untouched, then the alarm has no reason to fire.

Disconnecting the fuse

Disconnecting the fuse is a similar alternative to disconnecting the battery. However, instead of killing the power of the entire vehicle, you are just killing the power of the alarm system itself.

While this can be an easy way of disabling your alarm, most car fuse boxes are located somewhere underneath the dashboard, which means you need to be able to access the vehicle’s interior and know which fuse is responsible for the alarm.

Cutting the wires

Another option is to simply cut the alarm system’s wires. While this will permanently damage the aftermarket alarm, it will also permanently disable it.

If you want to remove the alarm system, cutting the wires is an easy way to do so.

Using manufacturer-specific tools

Most aftermarket car alarms can be reset using the key fob or a dedicated switch. However, some systems also offer other ways of resetting the alarm.

Advanced aftermarket car alarm systems include apps that enable you to reset the alarm using your smartphone. Others have key patterns you need to follow by inserting and removing the key from the cylinder a set number of times. Check your aftermarket car alarm’s manual for the specific combination.

The best way of resetting your aftermarket car alarm

While there are several methods for resetting your alarm system, the best and simplest is to use your key fob. Unless your alarm system is faulty, the key fob should always be your go-to.

However, in case you need to try another method, consider the ones we’ve explained here. Remember: if the alarm has no power, it can’t function.  


In conclusion, resetting an aftermarket car alarm may seem daunting at first, but with the right information and tools, it can be a straightforward process. By locating the reset button, following the manufacturer’s instructions, and troubleshooting any common issues, you should be able to reset your car alarm with ease.

Remember to always consult your car manual and the manufacturer’s instructions before attempting any repairs or maintenance on your vehicle.

Keep in mind that resetting a car alarm can vary based on the brand and model of the alarm, so it’s important to understand the specific steps for your system. Overall, the process of resetting a car alarm is an important step in maintaining the overall security of your vehicle and keeping you and your belongings safe.

Hope we helped to answer your question about how to reset an aftermarket car alarm. If you are interested in car related tech you might be interested in our other article: How to Tell if Your Car is Bugged & What to Do

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Thomas S.

With a background in government supply and a keen interest in emerging technologies, I have developed a passion for the realm of stealth technology. My expertise lies in analyzing the latest advancements in spy gadgets and high-tech products, with a particular focus on those available to the public that offer a modern-day James Bond experience. Through my work, I strive to uncover the most cutting-edge innovations in the field and provide valuable insights to fellow enthusiasts and industry professionals alike.