Car Alarm Keeps Going Off (Causes & Solutions)

Do you experience a situation where your car alarm keeps going off?

The main purpose of having a car alarm is to prevent thieves from stealing cars, but it’s become usual for the alarm to go off, even when there’s no danger nearby.

It can be embarrassing and if you’re experiencing this, you’ve come to the right article!

In this guide, you’ll get enlightened on why the alarm always goes off and also hacks that’ll solve this embarrassing problem.

Let’s get started!

We have highlighted some reasons, why your alarm may be behaving unusual and also ways you could get it fixed, below.

1.When the Key Fob Stops Functioning

A small plastic controller used for keyless entry in systems is called a key fob. This key fob has a short-range radio transmitter, used to send distinct signals to the car’s receiver units. When it’s functioning properly, the controller locks and unlocks car doors & jump-starts the car ignition, just with a push button ease. When it’s faulty, it won’t be able to send signals to your car receiver units properly, which results in your alarm buzzing.

Recommended Solution

Key fobs batteries die when you use them for a long period. In this case, replacing the battery should solve the problem. If you also feel your key fobs are not acting as they should, separate them and check if there are any broken contact or skewed buttons. When the connection checks out, you might have to scan the key fob with a code reader, or program the controller again, either seek help from a professional or do it yourself.

Car Alarm Keeps Going Off (Why and How to Fix)

Also Read: What is a Powertrain Warranty (Everything to Know)

2. A Malfunctioning Hood Latch Sensor

Other sensors that are in the car, apart from a controller that’s malfunctioning, might trigger the alarm to buzz randomly. For example, a good latch sensor is made up of simple electrical switches and senses if the hood opens or closes. So a functional hood sensor senses when the hood latch opens and loses the electrical switch then shows a warning light on the dash. But if it’s a defective hood sensor, the alarm goes off instead – it does not matter if you’re driving or it’s late at night.

Many factors make up a faulty hood sensor, but the most common factor is dirt. The sensor is prone to dirt, engine grease, and debris because it sits mostly in the car’s engine bay above its headlight frame. This makes it malfunction and triggers false alarms.

Recommended Solution

Keeping the actual sensor and hood latch clean doesn’t just stop false alarms, it also protects the car from damage and theft. Good brake cleaning brushes and cleaners, are all you need to clean the sensor of the hood latch. If you’re still hearing the alarm after cleaning, it means the hood sensor might be bad or has been tampered with, by someone. Anyone it is, replace it immediately.

3. A Feeble or Excess Sensitive Sensor Connection

Every car has a different movement and shock sensor type. For example, older cars normally have just 2 sensor types – a shock and a door sensor, while modern cars have more. Also, older sensor types have fixed settings, whereas new ones might be adjustable.

Similarly, a sensor’s sensitivity depends on either an aftermarket alarm system or a factory. A perfect example of the difference in sensor sensitivity is a Volkswagen and Audi car; both are known for having oversensitive sensors from the factory.

Recommended Solution

It’s important to check for solid electrical connections on all the sensor feeds because they can turn off your main battery. If you’re unsure what you should be looking for, go with your car to an auto shop in your area, to have them check your car alarm professionally.

4. Weak Hood Latch Connection

Sometimes, the car alarm would go off, after you’ve replaced or cleaned its hood latch sensors. Consider checking for a defective connection in the hood latch, if this is the case. Even though this type of problem rarely happens, ensure you avoid disregarding it. If your hood latch isn’t good, it could trigger false alarms and affect the car’s control unit adversely, leading to wrong readings and commands like turning on your airbag light, even when there are no problems with the airbag.

Recommended Solution

When you don’t see any damage, disconnecting and reconnecting the connections of your hood latch, usually gets it to work. Another thing you can try is inspecting the connection of the hood latch, to find any of these: wear, cable binding or fraying, misalignment, damage on the actual hood latch, pull handle assembly’s condition, or settings of the rubber stop on your hood. Find out if the springs or levers are bent or worn out. Depending on what you find, prepare to spend up to $240, with labor costs added.

5.When the Door Lock Sensor Is Bad

Another thing that’s capable of making your alarm go off, is a door lock sensor. The sensor always has 2 wires – a closed and open circuit, installed in the actuator’s door lock. Due to its setup, door lock sensors can misbehave during the rainy season, when water could slip into door lock actuator connectors. The internal wirings eventually fail. In addition, their release cable brackets on the actuator could break, for specific car makes and models.

Recommended Solution

If you identify the source of water leakage and seal the connector using protective grease, it helps in fixing the problem. Next, inspect the door lock actuators to find out if they work via door switches or key fobs, and watch out for humming or buzzing sounds accompanying it when you hit the switch, this also helps to narrow down this Issue.

If the case is faulty wiring, a scan tool can help you find out the car door that has made your car alarm go off continuously. When you find out the door, you must inspect the actuator and lock connector of the door, to know if you’re to replace any of the parts.

6. Weak Control Unit

Electronic Control Unit or ECU is becoming more complicated with new car models. They’re designed for processing plenty of information & mechanical operations, which often are integrated with your car’s alarm control units.

When an ECU develops an issue, it could send false signals to different car components, misleading the alarm system to think that the car’s security is being compromised. When this is undetected, it might lead to instances that could bother you, like your alarm randomly going off continuously.

Recommended Solution

From everything we’ve listed, you can’t diagnose this particular one yourself. Take your car to a car specialist, because that person will have the right tools for dealing with the problem. If it’s this that’s setting off your alarm, then your ECU ultimately needs reprogramming.

7. Low or Dead Battery Voltage

A bad car battery can cause plenty of trouble, including having your alarm buzzing randomly at night. The car’s battery powers your car alarm, and the alarm might go off to alert you when the car battery is getting low. The best logical decision is to replace the battery.

Your car alarm buzzing, isn’t the only way to know your car battery’s getting bad. There are other signs, like when you have problems starting your car, having dim lights, getting battery warnings on your dashboard, and more.

Another related issue might be an issue with your battery terminals. Specifically, a corroded battery terminal might indicate false problems with the battery itself.

Recommended Solution

If the corrosion amount is small, you can clean it with the right agents. when you do, ensure you’re certain of what you’re doing, and your safety should be prioritized. If this does not fix the problem, I suggest you buy new batteries.

8.When an Alarm System Is Poorly Installed

The factory alarm system only provides basic anti-theft protection, and security to a certain extent. The limited protection is one of the major reasons most car owners go to the aftermarket, for car security solutions. The negative is that the car alarm in the aftermarket is usually not installed properly, especially if it’s done in the home garage. A sign that a security system is installed incorrectly in a car, is if the car alarm goes off continuously at night.

Recommended Solution

When you install an alarm system yourself, double-check all instructions on your installation manual, to be sure you did everything well. But, if the professional mechanic does the job, go to the auto shop the job was done and explain your problems. Usually, If the alarm system is reinstalled properly, it solves the problem.

Check out this video to know more about this problem and its solution.

How to Turn Off a Car Alarm

The only thing that could make an alarm randomly going off worse, is when you’re not able to properly turn it off. So it’s best to be prepared always, and the best way to achieve it is by reading your owner’s manual. When you don’t get all you’re looking for in the manual, try these few things.

Simply Lock and Unlock the Car

Pressing any button on your key fob is usually enough, but if it’s not helping, try locking and unlocking your car manually using the key.

Most cars have a mechanical key that’s small in their key fob, and they’re usually hidden.

You can use your regular car key or that key if it’s exposed already, to try locking and unlocking your car a few times, through the car’s driver’s door.

If, after all this, the alarm still refuses to stop, start the car. Sometimes it’s even necessary for you to drive it a bit.

Disconnect the Alarm Fuse

Deactivating the alarm totally by removing your alarm fuse, is a drastic approach. This situation requires your owner’s manual because the fuse box location is mentioned there.

It’s sometimes difficult to access the fuse box, therefore, be careful when trying to get it open to avoid damaging the parts around the box. When you’ve correctly identified the fuse, remove it simply, and the alarm will stop immediately.

Sometimes, an aftermarket alarm won’t stop because then the fuse is used only for the factory alarm. When you find yourself in that situation, try locating one small box which usually comes with an aftermarket alarm, and disconnect it.

Remove the Battery

Battery disconnection should be done, only as a last resort. Just like you always do when dealing with car batteries and electricity, ensure you’re cautious and always work using protective gear.

There’s a very good guide you can find on wiki How, showing how you can safely disconnect a car battery. It might be that your alarm works perfectly even after it has been disconnected, but that’s rare.

Also Read: Brake Lights Stay On (Causes & Solution)

Frequently Asked Questions -Why Does My Car Alarm Keeps Going Off?

Why does my car alarm keep going off?

There are several reasons for your alarm to keep going off. Amongst all the reasons, some may be quick and easy to fix, while others can be signs of bigger problems. The common reasons why an alarm goes off are as follows:
A key fob that’s not functioning, a sensor connection that’s either too sensitive or weak, a faulty door lock sensor, a defective hood latch sensor, a dead car battery or low battery charge, a poor hood latch connection, a faulty electronic control unit and poorly installed alarm system, etc.

Can I disable my car alarm?

In most modern cars, they have an off switch for the alarm system fitted in. The car manual will show you where it is located, but it’s mostly found close to the bonnet or petrol cap.
That being said, most models and makes will deactivate an alarm if the car is simply locked, using a physical key instead of using the fob.
The owner’s manual has a section informing you on how to deactivate your car alarm.

How do I locate the fuse box in my car?

The car usually has 2 fuse boxes. You can find one under the car hood, and the second near your steering wheel or on the car’s dashboard. The alarm fuse is likely located in the fuse that’s under your car’s hood.

What should I do if my car alarm keeps going off?

Firstly, call 999 if you suspect someone is trying to break into you or your neighbor’s vehicle. But if your alarm is dodgy and keeps ringing, inspect your car carefully to find out where the problem is coming from, and take proper measures to fix it completely.

How do I know when my alarm sensors are faulty or oversensitive?

Luckily, there’s an easy way for you to know if the sensor settings are set to be too high. Just give the car a little bump to see if the alarm goes off.
The shock sensor can be adjusted by moving your adjustment dial. For example, to turn it down, turn the dial counter-clockwise.

Final Thoughts – Why Does My Car Alarm Keep Going Off?

Next time you wonder, “Why is my alarm going off continuously at midnight?” you should now be capable of solving the Issue without hassle.

The information in this guide will not only save you from embarrassment and fines, but it’ll also make sure that your alarm system functions properly – asides from guaranteeing you & your neighbors a good night’s sleep daily.

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