Home Diagnosis and TroubleshootingSecurity Systems, Keys, and Alarms Car Alarm Keeps Going Off – How To Fix This Annoyance?

Car Alarm Keeps Going Off – How To Fix This Annoyance?

by Jordan Harris
Car Alarm Keeps Going Off

Your car alarm keeps going off by itself can be one of the most annoying things ever if you are a car owner. Even if you are just a regular pedestrian, you probably hate it when you walk down the street and suddenly a car alarm goes off. It can easily scare you, or put on alert the whole neighborhood.

If your car does this on a regular basis, you need to take care of this issue and stop the car alarm from constantly going off. You don’t want to become a problem in your neighborhood and your neighbors to start hating you because your alarm wakes them up at 2 am.

When you fix this problem, you will also benefit. You will not wake up every night to turn it off and also you will sleep better. Another big reason why you should take care of this issue is just that the car alarm may eat your car battery. You don’t want to get your battery drained from the alarm that was going off for 10 minutes straight.

There are many symptoms and solutions on why this annoyance happens, and we are going to discuss them in this article. And also, we are going to share some better alternatives to car alarms that are more effective when it comes to car thefts and break-ins. So, if you want to learn how to fix this issue once and for all, follow along.

What Is A Car Alarm?

A car alarm is an electronic device planted in your car that has a goal to discourage a potential theft of the vehicle. These alarms are working by emitting a high-volume sound when the alarm is triggered. These sounds are usually a combination of the vehicle-mounted siren and a prerecorded sound that immediately catches everybody’s attention.

These alarms may also cause the vehicle to flash the lights and blinkers. Some of the car alarms are more advanced and have extra features. For example, some alarms notify the owner by a cellular phone if a theft on his vehicle is underway.

OEM Alarms vs Aftermarket Alarms

Most of the OEM alarms are armed and disarmed by the keyless entry device that we use to unlock and lock the doors. On many vehicles, the OEM alarms work in a way that the key cylinders on the front passenger doors activate the switches. So, when these switches are activated by pressing the key fob, the alarm on the door will arm and disarm.

Some vehicles will even arm the alarm even before the door is closed, but the key is pressed. Some vehicles disarm the alarm when the key is on the ignition and it’s turned on. Especially when the vehicle is equipped with both an alarm and immobilizer. The valid key code that is on the key when inserted in the ignition will turn the alarm off.

Aftermarket alarms, on the other hand, arm and disarm the system using a seperate remote control. They usually cannot disarm an alarm from the key cylinder-like OEM alarms.

What Triggers The Alarm?

Usually, the aftermarket alarms are the easiest to trigger. Because they come as one-piece units. These units have a siren and a control module. The sensor they use is called a shock sensor. This shock sensor is sensitive to vibrations. Making it easy to trigger. A simple revving of an engine car triggers these alarms and alerts everybody around. Also, this shock sensor may be triggered if the car is towed and even if it’s slightly touched by someone.

Because of this, these aftermarket alarms are not recommended. Their effectiveness is quite low in comparison to immobilizers and other tracking equipment.

OEM alarms on the other hand have sensors on the latches of the hood and the trunk. Making them much harder to go off and cause mayhem. They are also much more friendly for the environment and will not wake up you and your neighbors in the process.

Effectiveness of The Car Alarms

The effectiveness of these alarms is questionable. Although they were popular in the 80s and 90s. The present usage of these alarms is also kind of useless in most cases. Because many of these alarms are so easy to trigger and they go off for no particular reason. Because of this issue, many people have the tendency to just ignore them.

And authorities reported that because of these easy triggering alarms, car thefts became even more frequent in New York. The sound of these alarms makes it easier for the stealer to conceal the sound of breaking the window open by force.

Because of this issue, many car makers have started offering silent immobilizers. And also, there are many aftermarket options for GPS tracking systems that are easy to install. And these systems can locate a vehicle through a satellite. If your car gets stolen, you just turn on the app and get your vehicle location in two clicks. But be careful where you install these tracking systems. Many of the thieves may notice them if the tracking system is placed in some obvious place. Many of the cars get stolen and get disassembled so keep this in mind.

You can also get a system that will even disable the starter of the vehicle. And I think would work the best for most people. Along with a GPS tracking system, this is probably the winner combo.

Reasons Why Your Car Alarm Keeps Going Off

Car alarms are really annoying when they go off for no particular reason. But there can be a perfectly good explanation for this situation. In this chapter, we are going to discuss one of the most common reasons why your car alarm keeps going off. Later we are going to add some solutions on how you can take care of this issue all by yourself in DIY style.

Broken Key Fob

A broken key fob may easily turn on your car alarm. We use key fobs to lock and unlock our cars on a daily basis. These key fobs are known to break, especially if you are using yours for a very long time. These fobs are mostly located in your pocket and over time they have the tendency to run out of power. With time, the battery gets empty and it may cause the alarm to go off. Shorting is also one of the issues that these key fobs are having trouble with. This may cause it to send a wrong signal to your battery and cause the alarm to go off.

Also, low-quality Chinese aftermarket car alarm systems or knockoffs have one of the worst key fobs out there. They are not well known for their quality of manufacturing. They implement some basic electronics. This technology is not the best out there, and these are more prone to drain the battery earlier than expected and are also prone to short out.

Car Battery Running On Low Power

A car battery should always be filled with power. Don’t leave your battery empty. Especially if you are running car alarms and other auxiliary electrical devices that require electricity. This may cause your battery to drain fast and cause the alarm to go off.

When your battery is running low, the car alarm may go off and start alerting everyone. That situation will tell you that you need to fill up the battery with electricity, by running your car.

When you turn on the car, the alternator will start spinning and the battery is going to slowly fill up. Then you are ready to go. This problem happens to cars that are rarely driven or aren’t driven at all.

If you own a car that is rarely driven, it’s not a bad idea to buy a charger that you can plug into your wall. When connected, this charger will keep your battery always full with electricity. Problems like this one, with the alarm setting off, will be things from the past.

Also, a better-quality battery is always a good idea. Get a battery from a decent brand that will last for many years. Most of the batteries die off after the warranty goes away, but that is not the case with more quality brands. There are some manufacturers that are producing batteries that last for 5-10 years with no problem.

Bad And Corroded Battery Cables

Another reason why your alarm may go off is bad and corroded battery cables. If this happens to you, it is a good idea to open your hood and check the battery terminals. These terminals should be perfectly clean.

If they are worn out, they need replacing with new ones. Because when these terminals are bad, they can also get the power out of your battery quicker than usual. This may leave you stranded someday. You don’t want your car alarm to keep going off and also a situation that will make your car inoperable.

Broken Hood/Trunk Latch Switch

Hood and trunk latch switches are installed by the factory. These switches are only included in OEM car alarm solutions and you will never find them elsewhere. These switches are created for a specific purpose, in the case, if someone tries to open your trunk or hood. They will send a signal to the alarm and the alarm will go off. Here Is a video on how a guy diagnosed the issue and fixed it.

This alarm then will cause the burglars to get scared and run away from the crime scene. These switches are known to go bad and cause some false positive signals. They will trigger the alarm for no specific reason and the alarm will go off.

Alarm Installed Not Properly

Alarms are not that easy to install. And if you do not follow the instructions from the manual exactly. Or the guy that has installed your alarm hasn’t followed them, it may cause your alarm to go off all of a sudden. Getting the electrical connections right is the key to making a properly working alarm, that will function only when the required conditions are met. And those conditions are vibrations or brute force.

Too Sensitive Shock Sensors

Some alarms are more trigger happy than others, and you should pay attention to this when you’re getting a new alarm for your car.

This is caused by the quality level of the shock sensors that come with the alarm. Some of these sensors are very quick to react and cause the alarm to go off because of some very minor vibrations and shocks.

These shocks may include some unintentional bumps by pedestrians. A cat may also jump on your hood, or some guy is revving up his Porsche next to your car. Yes, although it’s hard to believe, even some high-sounding exhausts may turn on these alarms and cause the whole neighborhood to wake up.

That’s why even when cars are vandalized and alarms go off. People don’t care at all. These false alerts are ruining the car alarm reputation. And make the alarms useless in real-life situations.

If your alarm is too sensitive, check if there are options to adjust the sensitivity. In order to make it less sensitive and less prone to go off.

Car Alarm Going Off By Accident

Although it is hard to believe, car alarms may go off by accident. For example, if you press the alarm button by accident, or you gave the keys to your son to play with them. He may have pressed the alarm and the alarm went off.

These situations happen on a daily basis and you shouldn’t always worry if your alarm goes off. It may probably be caused by an accident, for example, your cat climbed on the roof of your car, or a dog had rubbed your door. You never know what may happen.

The important thing is that you should not panic. Because everything has a proper answer and a proper solution. And we are going to discuss all the solutions for these issues in the next chapter.

Car Alarm Keeps Going Off, How Should I Stop This?

Your car alarm going off all the time is probably one of the most annoying things that happen to you on a daily basis. When it goes off, you are probably getting anxious and you run to your car. Thinking that someone is stealing from your vehicle but in the end, it’s just another false alarm. We explained the reasons why your alarm goes off. Now let’s see the solutions for each of them.

Broken Key Fob Fix

If a broken key fob is the culprit that causes your alarm to go off all of a sudden. The first thing is to check out the battery. Replace the battery first. They are easy to find and do not require any special knowledge to install. If you want you can search on YouTube to get proper information about this process. These batteries are fairly cheap. Costing less than $10. It is also a good idea to get a high-quality battery. It will last longer and also prevent failures.

If you suspect that the key fob is broken. You may want to replace it. There are shops that are doing this type of work and they can get your key fixed for $50.

Battery Is Running Low On Power Fix

For this problem, the best solution is to get a brand new battery. Get a battery made by a quality manufacturer and it will last you for a long time. The cost of a new battery will be depending on the capacity of the battery you need. The average cost is around $100. You can install the battery by yourself. It is a fairly simple process. Just loosen up the screws on the terminals and unbolt the clamps.

Car Alarm Keeps Going Off - Replace/ Charge battery

Remember, when getting a new battery, you need to get the right terminals. Plus, and minus should be on the same side as your old battery. If you don’t get these things right, you will probably not be able to mount the new battery. Because the cables won’t reach the proper terminal.

If your battery loses power then it’s a smart thing to check the electrical components and also you need to check your car alarm. Because maybe it is draining too much power. These low buck alarms are known to cause battery drain and car alarm keeps going off situations. So, if your battery drains too much that could be the culprit.

Also, make sure that you drive your car more often. Your battery needs to be charged all the time. If you are not driving your car, just unplug the positive cable from it. In this way, your battery won’t drain. The downside of this is that your car alarm won’t work.

If your car is parked in a garage. It is useful to use a wall charger to keep your car battery always at 100% charge.

Corroded Battery Terminals Fix

Open up your hood and check if the terminals are clean. If they are all corroded, then it’s the best idea to get a wire brush and clean them from the rust. This will improve the connection and will improve the power delivery.

If your battery terminals are rusted out and beaten up, then it’s also a good idea to replace the wiring. Replace the positive and negative cables with new ones, and you will be good to go. Cables can corrode and go bad with the years. So, sometimes this is the only solution.

Car Alarm Not Installed Properly Fix

Another important thing in preventing this problem with the alarm going off is that the alarm should be properly installed. Alarms have manuals along with them that will guide you through the installation process. Make sure that you follow them, and if you think that you missed something. Go through the user manual again and check the directions. Make sure that you get all the electrical connections right and you will be good to go.

Broken Hood/Trunk Latch Switch Fix

These switches usually come with OEM car alarms and they are known to go bad. Take a voltmeter and check if they are making 12V at their connections. If they are good, then you should look at your problem elsewhere. If they are broken, you will need to find a proper replacement for these switches. And they can be pricey. Depending on the prices that were set by the dealership, they can cost from $50 and go up to a few hundred dollars.

If you want to get these switches, you can search online. There are plenty of stores that are offering these switches and they are quite good in my opinion.

Also, if you have aftermarket switches that you installed with your aftermarket alarm, search online for these switches. These will be quite a lot cheaper since you can get them from almost every major online store.

Too Sensitive Shock Sensors Fix

Another reason for the car alarm keeps going off situation can be too sensitive shock sensors. These sensors as we said, are sensing the vibrations that are happening in your car and outside of your car. It can be easily triggered and your alarm will go off.

In order to prevent this issue, it is a smart idea to see if you can lower the sensitivity of your aftermarket alarm. Some alarms offer this option but some don’t. Those who don’t offer this option are usually the cheaper ones.

If you can’t reduce the sensitivity and your car alarm keeps going off. Better find a new higher-quality alarm for your car.

Car Alarm Keeps Going Off: Facts You Need to Know

  • A low or dead battery in the entry key fob is a common cause of a car alarm going off for no reason.
  • Cleaning the dirty bonnet latch sensor can help solve the problem of an alarm going off unexpectedly.
  • Poor installation of a DIY car alarm system or failure of one of its components can cause the alarm to sound and may also invalidate insurance.
  • A low car battery or worn-out battery terminals can interfere with the flow of electricity and set off the alarm.
  • Faulty or overly sensitive sensors in the car, including door sensors, proximity sensors, tilt sensors, glass break sensors, and microphone sensors, can cause the alarm to go off unexpectedly.
  • Locking and unlocking the car doors, turning the car on, or disconnecting the battery can be quick solutions to silence a persistent car alarm.
  • If a car alarm keeps going off, it’s best to get it checked by a qualified professional to avoid being charged with a statutory nuisance and potential insurance invalidation.
  • A factory-fitted car alarm may still be covered by the manufacturer’s warranty, but a later fitted one by an unapproved mechanic may void the warranty.
  • A car alarm’s sensitivity on individual sensors can sometimes be adjusted or deactivated.
  • Regular maintenance and replacement of batteries and other components can help prevent unexpected car alarm sounds.


We came to the end of this article and let’s sum things up really quick. Car alarms are very annoying especially when they go off for no particular reason. This can be very annoying for you and also for the people around you.

We discussed the main reasons why this situation occurs, and that is probably the oversensitive shock sensors. Sensors are components that usually make the alarm go off and if this happens too often to your car, then it’s better to see if you can reduce the sensitivity, or find some sensors that are less sensitive to normal situations that don’t force the car alarm to go off.

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