Car alarms work well at deterring thieves and alerting owners when someone has tried to tamper with their vehicle. However, when your car alarm goes off for seemingly no reason, this can be a loud and irritating inconvenience. If you own a car, chances are your car alarm has gone off at some point without you knowing why.
Car alarms are installed to protect your car from thieves, so why does a car alarm go off when unlocking your car with the key? In this article, we explore the different reasons why your car alarm goes off when unlocking with a key. This noisy problem is very common and can easily be fixed.
Car alarms act as a theft deterrent, the loud noise they emit is designed to scare potential thieves away and alert the car owner that a theft attempt was detected. However, sometimes your car alarm will go off when no one has tried to break into your vehicle.
Modern car alarms are made up of various pieces; a computer, several sensors, a loudspeaker, and a receiver that is tuned to your keycode. Your car alarm is triggered when one or more of the sensors receives a response, this can be from the car moving when the engine is off, a loud noise, or something landing on or near the car.
When a sensor receives a response the car alarm sounds and will continue to make a noise until it is reset or switched off. Your car alarm is constantly active but will remain silent if no unusual activity is detected.
If you are wondering why does my car alarm goes off when I unlock it with a key, we have the answers here for you. There are many reasons why a car alarm goes off when unlocking the door with a key.
A car alarm is triggered when its sensors receive a response either from a sound or movement. However, if your car has particularly sensitive sensors, they can be triggered when you try to unlock the vehicle by putting the key in the lock.
Oversensitive car alarm sensors can be activated by the sound of a dog barking nearby or even just by someone leaning against your car!
Solution
Fixing over-sensitive car alarm sensors doesn’t require a trip to see a mechanic. Using your car manual, locate the alarm and follow the guidance in your manual to reconfigure your sensors. Once you have successfully reconfigured your car alarm sensors they will be less sensitive and will not be triggered when you are just trying to unlock the door.
If your key fob (or remote key) is faulty, your car alarm may go off when you unlock your car. The key fob will deactivate the alarm system when you press the unlock key, however, if the remote is faulty or the battery is dead, the alarm may stay on, and when you then open your car door the car alarm will sound.
To fix this issue you may only need to replace the battery in your key fob. However, if the problem persists the key fob may need to be reset or completely reconfigured.
When you lock your car using the remote key fob, the car’s security system is activated. The dome light circuit alerts your car alarm when a door has been opened, if your door is opened with a key in the lock and not by pressing a button on the key fob, your alarm will be triggered.
This happens because your car does not know if it is the car key or someone picking the lock that has opened the vehicle door. Your key fob uses encrypted coding to lock and unlock your car, if the door is unlocked without your car receiving the signal from the remote key, the alarm will sound until you put your key into the ignition.
The easiest way to solve this problem is to always unlock your car using the key fob if you used it to lock your car. However, if you do accidentally set the car alarm off when unlocking with the key in the door, simply put the key into the ignition and turn it over. Once the key is recognized by the car, the car alarm will deactivate.
If your car alarm is being triggered at random times and when you try to unlock it with a key, it may be because your car battery is running low or is damaged. As the car alarm is run by the car battery, if there are issues with the battery this can also cause your alarm to function incorrectly.
Also, if your car battery is damaged, there is rust in the terminals or the battery is corroding, this can trigger the car alarm. If your car alarm is frequently sounding ‘for no reason,’ it may be worth checking the condition of your car battery.
You can check the charge of your car battery by using a voltmeter. If there are not enough volts running through the car battery you will need to recharge it. If the battery is dirty you can clean it using a car battery cleaner, just be sure to wear protective clothing.
If your car battery has become seriously damaged and corroded, you may need to replace it. Once you have a battery in good working order, your car alarm should stop going off when you unlock it with a key.
Your car alarm may sound when you are unlocking your vehicle if you have accidentally activated the panic button on your key fob. A panic button allows car owners to sound the car alarm by just pressing the button on the key fob (usually orange or yellow). This is useful in an emergency when you notice someone suspicious near your car, but it can be annoying when you activate it whilst trying to unlock your car.
This is an easy problem to fix. If you accidentally press your panic button, just press it again and it will deactivate. If your key fob stops working you can turn off the alarm by putting the key in the ignition and starting the car.
If your car alarm keeps going off in the middle of the night, it may simply be because your battery is low on charge. Driving charges your car battery but if your car is stationary overnight and your battery is running low, your car alarm may sound as it is run by the battery.
You may have a faulty hood latch sensor, a faulty door lock sensor or the whole alarm system may have been installed incorrectly. If your car has over-sensitive sensors, nocturnal animals may be to blame for your alarm going off in the middle of the night.
There are many reasons why your car alarm may be going off randomly. The car alarm may be oversensitive and sounds and movements in the close proximity of your car may be triggering the alarm to sound. There may be issues with your car battery or your car alarm system may not have been correctly installed.
A car alarm system is run by the car’s main battery. However, in many car models, there is a backup battery that powers the car alarm if the car battery is disconnected. For example, if thieves cut the car alarm cables connected to the car battery to avoid sounding the alarm, the car alarm can still work due to the backup battery.
A car alarm can drain the car battery but it will take a very long time to draw all the power and cause the battery to go flat. Whether your car alarm is in standby mode or it has been triggered, it will be using power from the car’s main battery.
It will take several weeks for a car battery to be drained by a car alarm in standby mode as the alarm does not draw much power from the battery when it is not activated. However, when an alarm is triggered it uses significantly more power and the battery can be drained in one-two day.
This is because when the alarm is triggered, power is needed to cause the alarm to sound and the hazard lights to flash. However, there are car models that will automatically shut the alarm off after a certain amount of time, to prevent the car battery from being drained.
Yes, having a car alarm in your vehicle will lower your insurance policy. Insurance fees vary between providers but many companies will offer drivers a discount if their car has an alarm system or other antitheft devices installed.
Car alarms may be useful for keeping your car safe from thieves, but your alarm sounding when you are just trying to unlock the car with the key can be extremely annoying. Don’t panic, this doesn’t have to become a problem you just put up with, there are many reasons why your car alarm sounds when you unlock the car using your key and the good news is they can all be fixed easily.
In this article, we have shared the five most common reasons why your car alarm goes off when you unlock it with a key. We hope you now know what to do next time your car alarm goes off when you are just trying to unlock the door.
