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How Long Do Car Alarms Go Off For?

Car alarms are designed to protect a car from being stolen. But most alarms don’t go off because a burglar is attempting to break in.

It’s common to hear car alarms going off all the time in a neighborhood, even during the day. These are mostly false alarms caused by external circumstances.

If a car alarm keeps going off in your neighborhood, it becomes a nuisance. In some states, owners can even be fined due to the disturbance.

Learn why car alarms keep going off, if a car alarm stops on its own, and what to do about a neighbor’s car with a faulty alarm system.

How Long Do Car Alarms Go Off For?

Standard US car alarms go off for around 30 seconds, and at most several minutes. Car alarms are designed to sound long enough to alert the owner to a break-in or fault. 

More advanced car alarms sound for as long as 20 minutes if they aren’t turned off by the owner or disabled by a burglar.

A car thief disabling a car alarm.
A car thief disabling a car alarm.

Does a Car Alarm Stop On Its Own?

Most car alarms stop on their own after several minutes.

Standard vehicle alarms don’t go off indefinitely. If they did, this would drain the car’s battery and cause a significant nuisance to neighbors.

Even though car alarms stop by themselves, it’s advisable to turn them off as quickly as possible.

Otherwise, it disturbs neighbors and gives cause for a noise complaint fine. In some states, a noise complaint fine is around $200 or more for a first offense.

What Triggers Car Alarms?

Car alarms are designed to be triggered by burglars attempting to break into a vehicle.

AlfredCam Plus being used to monitor a garage.

How Long Does a Car Alarm Battery Last?

Car alarm batteries start to deteriorate after 3-6 years, depending on the car and the quality of the battery.   

Since car alarms turn off by themselves after several minutes, one false alarm is unlikely to drain the battery’s power.

However, a car battery drains fast if the alarm goes off multiple times in a day without being disabled by the owner.

Why Do Car Alarms Go Off at Night?

At night, car alarms are commonly triggered by animals walking on or around the car. Some animals—like rats, raccoons, mice, and moles—nibble wires underneath cars at night, which triggers the alarm.

Alternatively, it could be a result of a faulty alarm system, low battery key fob, or locking system interference.

What Causes Your Car Alarm to Go Off For No Reason?

In any neighborhood on any given day, you can expect to hear a car alarm sounding at some point. This appears to be for no reason, since there’s usually no one near the vehicle attempting to break in.

False car alarms usually signal that something is wrong with the car or the alarm system itself.

The most common issues that cause false car alarms include:

1. Low or dead battery

Car alarm systems operate via the vehicle’s battery. When the vehicle is turned on, the battery charges itself.

If the battery is drained, both the alarm and the vehicle will no longer function properly.

Batteries in cars are usually drained by radios, internal lights, phone chargers, or headlamps left on for long periods.

Leaving these systems running for more than 3-5 hours without the engine being turned on drains the car’s battery.

Car batteries also sometimes go dead when the engine isn’t turned on for 1-2 months.

Some car alarms simply fail to activate when the car battery is dead. However, some alert the owner to a low or dead battery by triggering the alarm.

More sophisticated vehicles may alert the owner that the battery is low via a warning message on the dashboard or via a connected device.

2. Malfunctioning key fob

Key fobs and remote keyless entry devices operate via battery power. When the fob battery dies, it may stop working, signaling to the owner that it requires changing or recharging.  

In some vehicles, when the owner attempts to unlock a car using a key fob with a low battery, the alarm will sound. This can be deactivated using a spare key or by changing the battery.

Faulty key fob or keyless entry systems also trigger car alarms.

3. Faulty latch sensor

Alarm systems in vehicles are linked to all latches inside a car, including the door, hood, and trunk. When these are opened by force by a car thief, this triggers the sensors and the alarm sounds.

Should the sensors in any of the latches be faulty on the vehicle, this can cause a car alarm to go off for what appears to be no reason.

The alarm can be deactivated using the key fob or by fixing the issue with the sensors, if a fault is identified by a mechanic.

Can I Do Anything About a Car Alarm That Keeps Going Off?

If your car alarm keeps going off, address it by doing the following:

1. Notify neighbors and apologize in advance

Avoid the wrath of sleep deprived neighbors by informing them that the car is producing continual false alarms, which they can ignore. It might take a while to diagnose the issue, so warn them first.

2. Refer to car manual

Turn off factory car alarms by referring to the manual, which instructs drivers how and where to turn the alarm off. Turning off an aftermarket alarm is generally a lot more obvious.

3. See a mechanic or car alarm specialist

While most car alarms that keep going off are resolved by replacing the car battery, get a pro to identify the cause before investing in any new parts so that you don’t waste any money.

4. Disconnect the battery

In the worst case scenario, a short term fix to a car alarm going off constantly is to simply disconnect the car’s battery while you wait for a mechanic to arrive.  In the meantime, use a security camera with a built in siren to monitor the car so that your vehicle isn’t vulnerable.

What to Do if a Neighbors Car Alarm Keeps Going Off?

If a neighbor’s alarm keeps going off, this is unlikely due to an attempted theft.

Instead, a fault is likely causing the issue. It’s the owner’s responsibility to fix the fault, otherwise, it can be seen as a noise violation.

When a neighbor’s car alarm keeps going off, the owner should be approached or a note left on the vehicle asking them to resolve the issue.

Keep a record of how often the alarm sounds and when and how you notified the neighbor if reporting the issue to the authorities or making a noise complaint.

Conclusion

Car alarms won’t go off indefinitely. They go off on their own after a couple of minutes.

When a car alarm keeps going off, this might indicate a fault in the system. It’s also a sign that the key fob battery is low or that the vehicle is being tampered with.

A car alarm that keeps going off by itself drains the car battery. It’s also cause for a noise complaint, potentially leading to a fine for  the owner.

Car alarms are designed to protect the car from theft, but they are easily tampered with.

Fitting security cameras helps owners understand why a car alarm keeps going off, particularly at night, and if the vehicle is at risk of being stolen.