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Why Does My Car Alarm Go Off By Itself?

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An alarm system is a crucial piece of equipment for any car. Designed to go on if someone was trying to break into the vehicle, an alarm system works to protect your car by attracting attention to a possible break-in and deterring a would-be car thief. The system does this by sounding a very loud buzzer or siren and making all of your car lights flash to attract attention.

Unfortunately, no piece of car equipment works perfectly 100% of the time. Sometimes, a car’s alarm can be triggered even though there is nothing and no one around it. This could be a one-off incident that’s easy to deactivate using the alarm’s remote or key fob, but in a worst-case scenario the alarm could keep being triggered non-stop; a major problem for the car owner, especially if it happens in the middle of the night in a residential area.

It Won’t Stop; What Do I Do?

Assuming the car alarm keeps on being triggered despite it being disabled remotely, there is one other temporary solution you could use: disable the alarm manually. Some car alarms are designed to have an override switch that can be used in situations just like these, so check your car’s manual if you’re not sure where it is.

As a last resort, you might even consider disconnecting your car battery. This will disable the alarm system (and the car), until you figure out what to do next. Ideally, that would be to reconnect the car battery and drive it to an alarm system expert who can diagnose and repair the problem. If this happens in the middle of the night, or if for whatever reason you are too busy, it may take some time before that happens.

In the meantime, you may wonder why this seemingly mysterious problem may be happening in the first place. Here are a few possibilities:

Possible Reasons

A problem with the remote / key fob

Here’s one of the first suspects we might quickly overlook: the key fob, that is the actual remote you use to enable and disable your vehicle’s alarm system. Seeing as how these devices also have an option to sound the car’s alarm, it could be possible that something is wrong with it and is triggering that function.

Examining the key fob and its battery could be a way of seeing whether or not it is the source of the problem. Better yet, try and see if you have the same problem with a spare key fob if you’ve got one.

Dirty or faulty sensors

Automotive alarm systems are connected to a few sensors at important parts of the vehicle, particularly the car doors and the hood. These sensors are located at the latches that keep these doors and panels shut, and their sole purpose is to detect whether or not the door is open when it shouldn’t be.

If these sensors are dirty or faulty in any way, they could be falsely triggering the alarm system as if the car was being open without your permission.

Something to do with your car battery

In some cases, your car battery could be the one causing the problem! In some vehicles, when the car battery’s power is low it uses the alarm system to warn you so you’ll get it replaced. This, of course, depends on the make and model of the vehicle, so be sure to refer to your car manual to see if its supposed to respond this way.

If it is indeed designed to do so, there could be another issue happening. If the car’s battery terminals are damaged or rusty, that could be interpreted by the system as the battery being weak or that it’s dying, and could trigger the same response.

A problem with the alarm system itself

With all of those possibilities aside, the problem could be with the alarm system itself, specifically the electronic parts in the main unit. The alarm’s main unit is the ‘brain’ of the entire system, connecting all of the sensors on all of the doors and receiving signals from the key fob that you use to control it. If the main unit itself is faulty, that could also cause the alarm system to trigger without anything or anyone actually causing it to do so.

While this article provides possible reasons why your alarm is being triggered seemingly without a reason, an alarm system can be quite a complex piece of equipment. The quickest and simplest way to get to the bottom of the issue and resolve it would be to bring it to a car alarm specialist who has experience in dealing with such issues. They’ll be able to diagnose the issue and provide you with the best advice possible.