What to do if your car alarm keeps going off

A car alarm that goes off should never be ignored. At best, the alarm may be caused by a fault or an open window; however, in a worst-case scenario, a car alarm going off may be warning you that someone is try to steal your vehicle.

That's why we've created this guide to help you identify the most common reasons why a car alarm goes off in the UK.

Car alarms are designed to alert people to the fact that someone may be attempting to steal or break into a car. They are designed to attract attention and protect the vehicle and its contents from theft or damage.

They are particularly useful in areas where vehicle theft is common, or where a parked car may be at risk of vandalism or theft. The loud noise generated by the alarm is intended to attract attention and deter the would-be thief or vandal. This is the same for the lights flashing – especially at night.

In addition, car alarms can provide some peace of mind to vehicle owners, who may feel more secure knowing that their car is protected by an alarm system.

However, it's important to note that car alarms are not fool proof and can sometimes be triggered by accident, such as if someone accidentally bumps the car or if a strong wind sets off the alarm.

Car alarms are a useful security measure for protecting vehicles from theft and damage, but they are not a substitute for other security measures such as parking in well-lit areas, locking doors and windows, and using anti-theft devices such as steering wheel locks or GPS tracking systems.

If you are in a public or residential place, it can give the opportunity to neighbours or other members of the public to contact the police, if your car is being broken into.

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Many vehicles in the UK have a car alarm. However, there are few ways to make sure you do. First of all, if you have a local garage, you can ask them to check. You can also do this when you take it for an MOT or service.

There are a few other ways to check if your car has an alarm:

1. Check your car's manual: The owner's manual of your car should have information about the alarm system if your car has one.
2. Look for a flashing light: Many car alarms have a small LED light on the dashboard that flashes to indicate that the alarm is armed.
3. Check the key fob: If your car has a remote key fob, it may have a button that activates the alarm.
4. Consult your local dealership: If you're still unsure, you can take your car to a dealership associated with your make of car and ask them to check if your vehicle has an alarm system.

There are several reasons why a car alarm might keep going off. One of the primary causes of a false alarm will be a faulty system.

This is where the alarm system itself may be malfunctioning, which can cause it to go off at random times. This could be due to a faulty sensor or wiring. Take it to see a mechanic as soon as possible.

There may also be environmental factors that are setting off the alarm. External factors such as wind, rain, or even passing vehicles can trigger the alarm, especially if the sensitivity level is set too high or the conditions are extreme enough. It is also important to check that all of the windows and closed, as even a slight gap can allow an insect to fly into the vehicle and trigger the alarm.

You may also be suffering from key fob issues. If your car uses a remote key fob to activate the alarm, it's possible that the fob's battery is low or that the fob itself is malfunctioning. Replace the battery and see if that resolves it.

If the alarm to continues to be triggered, then you may have a wider electrical fault with the vehicle. Electrical issues such as a weak battery, a faulty alternator, or loose connections can cause the alarm to malfunction.

If you're unable to identify and resolve the issue causing the alarm to keep going off, it's recommended to take your car to a mechanic further inspection and diagnosis.

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The method for turning off a car alarm can vary depending on the type of alarm system in your car. It can also change depending on the make, model, and age of the vehicle.

If your car key has a built-in remote, you may be able to turn off the alarm by unlocking the driver's side door with the key instead of using the remote. This can help reset the alarm settings if there is a fault. 

Some cars also have a button on the dashboard with the word 'off' on it, which allows you to deactivate the alarm system. 

Should this fail, check the owner's manual. The owner's manual for your car may have specific instructions on how to turn off the alarm, so it's a good idea to check it if you're unsure.

If your car alarm is going off and you are unable to deactivate it, you may need to disconnect the battery to reset the system. The process for disconnecting the battery can be found in our guide, how to fit a new car battery, but should only be treated as a last option due to the fact it may wipe your car's onboard computer and/or infotainment system.

If the problem persists, seek the help of a trusted local garage, or mechanic.

There could be several reasons why your car alarm goes off in the middle of the night. Here are some possible explanations:

• Weather and local factors: Sometimes, strong winds or heavy rain can set off a car alarm. Also, if your car is parked in a location where there's a lot of vehicle or foot traffic, vibrations from these sources can also trigger the alarm.
• Electrical faults: If the car alarm system is faulty, it may go off. A faulty sensor, wiring, or control module can cause a malfunction.
• Key fob interference: Sometimes, interference from other electronic devices such as smartphones or other key fobs can cause your car alarm to go off.
• Attempted break-in: If someone is trying to break into your car, the alarm system may go off. It's possible that the attempted break-in is happening during the middle of the night when there are fewer people around to witness it.

It is strongly advised to not do this – as it will make it easier for thieves to steal the vehicle without any witnesses or way of tracking where they take the vehicle.

If your alarm has an issue – take it to a local garage or call for a mobile mechanic.

However, should you need to disconnect your car alarm, you will need to unlock the vehicle, start the electrics of the vehicle, remove the fuse and/or transformer connected to the alarm, then disconnect the battery of the car.

It goes without saying that disconnecting your car alarm is a risky thing to do.

Not only the physical act, as it can cause damage to your vehicle – but the results of the action itself.

It will make your car easier to steal – especially if it is parked in an area that is popular with thieves (such as dimly-lit roads, no CCTV, not in a Neighbourhood Watch area, etc).

If your vehicle doesn’t have an alarm, it can impact your insurance. So, be wary of this, too.

Should the worst happen, and your car gets broken into and taken away – if you have no alarm, it is unlikely any witnesses will be able to identify what happened and who did it.

In early 2023, Office for National Statistics (OBS) data revealed that car thefts increased by 29% compared to the previous year – highlighting a concerning trend for car owners.

However, there are some ways to help protect your vehicle alongside a car alarm – including some anti-theft devices.

Here are some examples:

• Wheel and brake locks – immobilises the steering wheel and pedals
• Wheel lock – using a key, you can lock the steering wheel in place
• Tyre clamp – an effective mechanism to stop a car being driven
• Tracker – this links to your smart device and can see where your car has been taken
• Faraday bag – keep your keyless tech safe by blocking thieves attempts to remotely access your vehicle
• CCTV – if you park on your driveway, capture any attempted break-ins on camera
• Doorbell alarms – these video doorbells can also capture movement out the front of your house and send footage straight to your mobile device
• Dash cam – capture footage from inside the vehicle

RAC Shop has a range of items that can help you protect your car.

Keep your car safe and use these best practices to protect your vehicle.

If you have any other tips for keeping your car secure, leave them in the comments below.