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Why does my car alarm keep going off?

Why does my car alarm keep going off and does it affect my car insurance?

Mehdi Punjwani
Written by  Mehdi Punjwani
Donna McConnell
Reviewed by  Donna McConnell
3 min read
Updated: 05 Mar 2024

If your car alarm is faulty or malfunctioning, it can be a loud and relentless nuisance that you might want to deactivate completely. But before you do that, consider how helpful they are as protection against vandalism and theft - as well as how your car alarm can affect your insurance.

Will a faulty car alarm invalidate my car insurance? 

Yes, simply put having a faulty car alarm may lead to your car insurance becoming invalidated, so you won’t be able to claim if someone breaks into your car or vandalises it while the alarm is faulty.  

man driving car

What causes a car alarm to go off on its own? 

Car alarms can be sensitive, and if malfunctioning they can sometimes be set off when you least expect it - often as a result of: 

  • Environmental factors: Your car alarm may be set off by the environment, like rough weather or a passing person or vehicle 

  • Faulty or dirty sensors: Your car has multiple sensors, and one may be faulty or have dirt and grime around it which causes your alarm to go off 

  • Open windows: If you’ve left a window open then insects or even debris from the road may get in and trigger an alarm 

  • Installation issues: There may’ve been an issue with the alarm’s installation, especially if it wasn’t fitted by the dealership or a qualified mechanic 

  • Key fob issues (battery or signal interference): Car alarms can often be set off by a low or flat key fob battery, while signal interference from devices like phones can also set the alarm off 

  • Car battery: A low, flat, or old car battery may also be responsible if it’s affecting power flow to your car’s alarm system 

  • Electrical faults: Lastly, any other wiring or electrical faults in your car may be causing power issues that set off the alarm 

Can I turn off my car alarm? 

You should be able to turn your car alarm off, both if it’s been set off and permanently thereafter if you decide it’s become too much of a nuisance. However, disconnecting your alarm entirely is likely to invalidate your car insurance policy if you need to make a claim for theft or vandalism, so consider if it’s the best choice of action. 

How do I disable a car alarm? 

If your car alarm goes off, you should be able to disable it through one of the following: 

  • Unlock the doors: Using your key fob to lock and unlock the doors remotely may turn the alarm off 

  • Use the switch: Some alarms, especially those installed separately rather than by the manufacturer, may have a manual switch or button you can use to switch the alarm off. If you installed the alarm yourself, check the instruction manual 

  • Start the engine: Some cars may require you to start the engine or at least turn the ignition switch  

  • Disconnect the battery: As a last resort you can disconnect the car battery’s negative connector to shut down the car’s power  

What if my car alarm keeps going off? 

If your car alarm persistently keeps being set off, you should get it checked over by a professional - and see if your warranty will cover repairs if your car is relatively new. It can be considered a statutory notice by the council if it continues and could even be removed - while you’ll likely need to pick up the cost of this. 

Does having a working car alarm reduce my car insurance costs? 

Yes, having a working car alarm, as well as other car security features like an immobiliser, can potentially reduce the cost of car insurance - but check with your provider to be sure. Remember, comparing car insurance policies with MoneySuperMarket is a quick and easy way to find affordable cover for you and your vehicle.