The car alarm inside your car is an electronic device that is designed to prevent the likelihood of felonious acts, such as grand theft auto and other similar crimes. Additionally, the alarm protects any valuable content inside your vehicle. These security systems work the way standard alarms work, by emitting a startling, high-pitched sound if the sensors are triggered.

The concept of car alarms dates a long way to the early 1900s. However, it took several decades before stock car alarms incorporated in vehicles were introduced for commercial use. The aftermarket design, however, was invented roughly 20 years before that.

Ironically, though this security device provides car owners with a highly effective way of deterring car-related crimes, your car alarm can become a problem itself. One frequent concern about car sensors is that they tend to go off randomly for no apparent reason.

For car owners, the experience can be quite a hassle because a faulty detector could send out a false alarm. Most people, however, find this dilemma extremely frustrating because of the annoying and startling noise it makes.   

Resolving the Issue

Troubleshooting this concern requires one important thing: knowing the root cause of the problem. There is more than one reason why a car alarm would sound off even though nothing appears to trigger it, and they are as follows:

  • Low Battery Voltage

There are a dozen things that could go wrong when your car’s battery has low voltage or is about to lose power. One of which is that it could trigger the car alarm system. Similar to a fast clicking turn signal which indicates the bulb needs to be replaced, a low battery activates the alarm to inform you that the battery needs a replacement.

For that matter, if the car alarm blares out suddenly in the wee hours of dawn, the first thing you should do is to take out your voltmetre and check the battery. The reading should not be lower than 12.6 volts. Otherwise, you may have to jumpstart the battery or replace it altogether.

  • Corroded Battery Terminal

Even though your battery is far from losing power, a corroded or rusted battery terminal is equally troublesome when it comes to your car alarm system. The corrosion creates a signal interruption, which gives off the impression that it has low power. As a result, the alarm will sound off, anytime, anywhere—even at the unholy hours of the morning, while you’re supposed to be asleep.

But why does this corrosion form in the first place, you ask? The simplest answer: chemical reaction. Car batteries contain water and sulfuric acid. Over time, the hydrogen gas from the acid seeps out of the battery. The instant the gas comes in contact with the terminals, the corrosion takes place.

In case you find corrosion on your battery terminals, you can use homemade products like baking soda and hot water to clean it off. Cover the terminals with baking soda before pouring a small amount of water on each connector. Then brush them off with a terminal cleaning kit.

  • Faulty Key Fob

Most modern cars have keyless features, allowing car owners to control their cars in any number of ways. When you press the ignition button on this tiny device, the key fob sends out a low-frequency signal, which tells the vehicle to start its engine. With this gadget, car owners can activate or deactivate any electronic connection in their car remotely.

As convenient as this gizmo sounds, a key fob can become an object of frustration if it becomes faulty. The primary reason a key fob could malfunction is if the contacts are loose or the buttons are damaged. Another reason is if its battery is beginning to lose power. You can refer to the owner’s manual if you need help in prying open the battery compartment or in identifying the type of battery for your key fob.

  • Unkempt Latch Hood Sensor

A hood sensor is an electric device that would go off the moment it detects that the hood is not latched properly. The purpose of having a hood sensor is to warn the driver of felons who want to pry the hood open.

There are instances when dust or dirt could get into the latch. When it does, either the latch could become dysfunctional or the sensor would fail to detect that the latch is working properly. Either way, this could trigger a false alarm.

Fortunately, cleaning your latch hood sensor does not require too much time, effort, or money. All you need is a brake cleaner and a cleaning brush to get rid of the dirt that has accumulated around the hood latch or sensor. If the device becomes defective, however, consider enlisting the expertise of a mechanic.

  • Badly Installed Car Alarm System

Car alarm systems provide drivers with a level of protection and security from car theft. For someone who owns a car that is not equipped with an alarm system, installing an aftermarket sensor seems like a practical thing when safeguarding the vehicle from pilferers.

However, there are instances when the car alarm system could be installed incorrectly, and that could cause the device to sound off randomly. Or even not at all, which is twice as bad. Either way, it would be a bummer to get out of bed in the middle of the night only to find out it was a false alarm, or that something has happened to the car but the alarm did not go off.

In such cases, you’ll be wise to have the defective alarm system redone at the auto shop where you have it installed there. On the other hand, if you installed the sensor yourself, it would not hurt to double-check your work to ensure that everything is in working order.  

  • Highly Sensitive Sensors

Have you ever tried parking your car by the shoulder of the road and waiting until a large truck pass by and the car alarm suddenly goes off? If you have, chances are your car has overly sensitive sensors. For sure, this is the last thing you would want to happen at midnight, apart from watching your neighbours’ porch lights turn on one by one.

To solve this problem, you need to locate the alarm sensitivity box inside your car. Usually, this device is situated under the dashboard on the driver side of the vehicle. The car alarm sensitivity box has a dial that, if turned counter-clockwise, could lower the sensor’s sensitivity.

  • Issues with the Wiring or Circuitry

Since car alarms are electric devices, there’s a possibility that the wirings could be connected wrongly to other components of your car by accident. Instances like these may happen after you have had something repaired in your vehicle. One such example is that if any of the lights—say, the blinker, for example—starts to flash the instant the sensors are activated. Your best action here is to take your vehicle to have a mechanic that specializes in car electronics to fix the problem for you.

Quick Tips in Turning the Alarm Off

There are instances in which the first thing most people do when their car alarms go off in the tranquil hours of dawn is to panic. Regardless of the cause, the moment your car alarm lets out a loud, blaring noise, remember to perform any of the following:

  1. Activate the car locks remotely by unlocking and locking it again with the key fob. If this option does not work, you can always use a car key.
  2. Take off the alarm fuse. We suggest doing this option only if the key fob and unlocking and locking the doors manually did not work.
  3. Disable the alarm using the shut-off switch. Typically, this type of switch is present only in aftermarket car alarm systems.
  4. Reset the car alarm system. You can perform this yourself if you have a manual handy. Otherwise, you can have a mechanic do the resetting for you.

Long and Short of It All—Why Car Alarm Systems Go Off Randomly

There are several ways in which a car alarm system could go off randomly. However, that does not mean there’s something wrong with any of its components. As abovementioned, an alarm system blaring out for no apparent reason could mean something is wrong with the car battery.

Regardless, a standing issue with the car alarm system is not something you should take lightly. That’s because it’s not just you who going to be bothered by a malfunctioning car alarm system, but also your family members and your neighbours, too.