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Why Does My Car Alarm Go Off For No Reason

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Over time, we have been able to establish the fact that having an alarm system in the car is very important. It helps to add a certain layer of protection to the vehicle and lowers your insurance fee significantly. However, just like any other electronic, the alarm system of your vehicle can start to malfunction. Why does my car alarm go off for no reason? Is one of the questions we get from people who their car alarm systems are beginning to malfunction.

Why Does My Car Alarm Go Off For No Reason

First of all, there is actually a reason why your car alarm goes off. Your car alarm system could go off unnecessarily because it is actually being over sensitive. Yes, your car alarm can be over sensitive. So it now begins to go off at the slightest vibration or touch. This can be very annoying because the sound can be so loud that it constitutes a nuisance to the environment.

There are some car problems that require you fix but not immediately. But for a car alarm, there must be immediate response. So in this is post, we will not just be focusing on the reasons why your car alarm system goes off unprovoked. That will make it seem like we are dwelling on the problem. So we will be looking at the problem and solutions to fix it too.


There are lots of reasons why your car alarm could actually go off. We will outline some of them and closely follow them up with their solutions. So the following are the reasons why your car alarm could go off unprovoked with their solution found too.

Bad key fob

The key fob of your car is an electronic access to your car operated remotely. It is also referred to as the key chain of the vehicle. The key fob can primarily unlock or lock the car doors. But more modern versions can even start the car remotely.

This device can also set and reset the alarm of the car. Now this is the problem: the key fob operates on a small battery that could easily run down. When this occurs, the alarm could go off unexpectedly. Secondly, the key fob is usually kept in trouser pockets. This could also make you press buttons unknowingly when you sit down. These buttons trigger the alarm of the car and makes it go off.

Possible solution

The first thing to do is to check that the battery is low and change it immediately. The size of the battery is usually the size of wristwatch batteries. You can find it in supermarkets or grocery stores. If you get a good one, it can last for years before changing it. so replacing the key forb battery is a good way to resolve this issue.

Low car battery

Apart from the key fob giving issues when the battery is low, having a low car battery can have adverse effects on your alarm system. This is designed as a warning system, but it’s actually not needed if you really think about it.

Your battery is low and you have a signal on your dash board, so why then does it trigger the alarm when you turn on the ignition of the vehicle? If this is a one-off, then there’s no problem. But if it becomes regular, then it means your car battery is dying fast, or the terminals are getting corroded.

When this happens, the battery could be sending inconsistent power supply throughout the vehicle. And this for sure, will trigger the alarm.

Possible solution

If you have established that a low battery is the reason why your alarm system is going off indiscriminately, you should first use a volt meter to know what voltage is left in the battery. If your battery is less than 12 volts, this is an indication that your battery needs to be replaced. Depending on the quality of the battery, you could get one between $50 and $200.

Latch sensor

The hood of your car can go off anytime the lid is open by someone who should not be doing so. The hood latch has a sensor because a thief can hot-wire the car from the hood and drive off with the car. Now, if this sensor gets dirty either with grease, oil or road dirt, it begins to send signals to the alarm system randomly. This will make the alarm go off unannounced and begin to cause a nuisance.


Also, dirt is not the only reason why your car hood latch sensor can trigger the alarm system. If the latch sensor is not installed properly, it could make your car alarm go off on its own. So a poor connection and a dirty sensor is the problem here.

Possible solution

The first thing is to clean the sensor with maybe a brake cleaner and a brush. This should make the sensor return to good working condition and stop tripping the alarm system anyhow. If you do not know where to find the hood latch sensor, do well to check the operational manual for guidance. But it is generally found in the head light area of the car.

And then if the sensor is clean, maybe the next thing to do is to confirm the connection. If you notice it is not sitting pretty, kindly disconnect it and reconnect it again. This should resolve the problem.

Shock sensors

A lot of movements and vibrations of a vehicle is monitored by the car alarm system. This is necessary for it to be able to curb theft and hijacking.

However, shock and vibration sensors can become over smart sometimes, as stated in the second paragraph of this post. If you bump into an object unexpectedly or an object accidentally hits the car, even if it’s just a light touch, this triggers the alarm.

So some people, to test the sensitivity of their alarm system, they give their car some gentle nudging and bumps to see if it goes off. If the alarm goes off, then the alarm system will need to be recalibrated to become a lot less sensitive.

Possible solution

In stating the problem above, you will see that we have already started outlining the solution to the problem. The first thing to do is to give your car some nudging if you feel it’s too sensitive. If the alarm goes off, you can still adjust it manually.

The shock sensors of the car can be found in the main module of the alarm. You can find the main module under the seat of the car or the dashboard in the driver’s side of the car. It needs to stay hidden because if thieves lay their hands on this module, the car is as good as gone.


So when you get the module, look out for a box that has a dial. Adjust it until it becomes less sensitive. This might require that you give it some trials but at the end you will realize it’s worth it.


We have seen cases where the above measures were tried and still, the alarm still keeps blaring loudly. If this happens, the first thing to do is to at least find a way to deactivate the alarm system so the noise can stop. Some of the ways to deactivate the alarm system are:

  • Lock and unlock the door of the car with the car key rather than the key fob. This can serve as an override and stop the alarm noise.
  • Start the engine of the car with the car key.
  • Locate and disconnect the alarm fuse from the car’s fuse box.
  • Remove the battery from the negative terminal.


Alarm noises can actually become a nuisance and affect the surroundings when they go off indiscriminately. Well, don’t fuss about it. Just refer to the procedures in this post and get it fixed, yourself!