Considering how rampant car theft is, especially in recent years, a good car alarm is a great tool for keeping your vehicle safe. Unfortunately though, understanding how they work is a step most people skip, leaving them lost when they run into problems. If you’d like to know what actually triggers a car alarm, you’ve come to the right place.
Car alarms are triggered when a security sensor’s switch is closed. The closed switch sends a message to the control unit, which triggers the alarm. While sensors are primarily meant to catch thieves, they can sometimes be inadvertently triggered by animals, passers-by, and even the wind.
Car alarms, while useful, can also sometimes go off seemingly without reason. To help with this, I’ll walk you through some of the most common things that trigger car alarms. I’ll also explain how these alarms work beneath the hood, so even the most complex systems will be understandable.
Here’s a list of six of the most common causes:
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1. Wind
We might not consider wind as a potential disruptor to our vehicle’s peace, but it can indeed trigger your car alarm. Wind can cause objects, like branches, signs, or debris, to move and hit against your car, setting off the alarm.
Besides direct hits, strong gusts of wind can rock the car, giving sensors the impression of an attempted break-in. This is especially true in areas prone to storms or high winds.
If your car is parked outside, try to ensure it’s in a sheltered area, away from trees or loose objects. Car covers can also provide a layer of protection, though they too can flap in the wind and cause false alarms if not secured tightly.
Another solution, similar to dealing with animal-triggered alarms, is adjusting the sensitivity of your shock sensors. However, always ensure that the sensitivity isn’t reduced to the point where legitimate threats don’t trigger the alarm.
2. Animals
If you often have stray dogs or cats brushing up against your car, it’s possible that they could be triggering your alarm. Even the odd dog walker on a stroll can trigger your alarm if they let their pet get too close.
As with wind, the best way to prevent your alarm from going off when this happens is to reduce the sensitivity of your shock sensors. It’s important to be careful when doing this, though.
Reducing sensitivity to extremes might leave your car unable to detect a legitimate break-in.
3. Faulty Sensors
Sometimes, there’s actually nothing that’s actively triggering your alarm. This can be a shock and hassle for many people especially considering how loud alarms can get.
Unlike many of the other problems on this list, you’ll actually have to spend some money to find a solution here. Sensors can be quite delicate, and if you’re not the best with electrical wiring, it’s much better to take the car to a mechanic than to fix it yourself.
If you’re not ready to take it to a mechanic, the best thing to do is disable the problematic sensor. For cars that don’t have this option, you’d have to disable the security system entirely.
Of course, this is less than ideal as it leaves your car unprotected, so it should only be a short-term solution.
4. Faulty Key Fob
While not as common, a faulty key fob can sometimes be the primary culprit. Many key fobs feature a “panic” button which activates the car’s sirens. This can be a great thing to have in a pinch, as it allows you to raise an alarm when needed.
Unfortunately, poor wiring or an overall low-quality fob can cause trigger your alarm without warning. If you have a pet or child in the house that often gets hold of your keys, this can also trigger the alarm.
5. Low-Quality Security Systems
Aftermarket installations aren’t necessarily bad, but you need to have a good eye when choosing them. Many non-OEM sources can be shifty, skimping out on quality materials to maintain a decent profit margin.
This sometimes manifests with a constantly triggering alarm from poor installation or overall low quality.
OEMs are understandably expensive for most people. However, poor aftermarket installations tend to cost much more in the long run, as you’ll have to pay for installation, repairs, and maybe even a whole new security system if the first one goes bad.
These installations are also less likely to have warranties, so you’ll get no compensation if anything goes wrong afterward.
6. Low Battery
As unintuitive as it might seem, a low battery can actually trigger your car alarm. Although most sensors attached to the car’s alarm system deal with external signals, some sensors detect the battery voltage.
So what does this mean, and how does that trigger your alarm? Well, these sensors are put in place so the car can detect when it’s in use.
If a thief were to break into your car, turning on a light or even trying to start the car would alert the sensor since these things draw power from the battery. This triggers the alarm and alerts you to a break-in.
As a result, a low battery or a working battery with faulty terminals can cause your alarm to go off since the sensors will pick up a voltage drop.
How To Stop Your Car Alarm From Triggering
If your car alarm keeps going off and you’re starting to get the stink-eye from neighbors, then it’s time to do something about it.
Of course, if this is a hardware problem like a faulty sensor, then the best option is to visit a mechanic. However, if the problem is something else like wind or animals or the odd passerby, I have a few things that might work.
Use the Key Fob
Your key fob can be quite useful when managing your alarm. Since it allows you to activate or deactivate your security system from a distance, you can sometimes hold off on activating your security system in the evenings.
Rather than activating it as soon as you get home, you can hold off until it’s a little later. Since there’s less foot traffic at night, you’re much less likely to have passersby trigger your car alarm.
Use Windbreakers
Windbreakers can be anything from buildings to trees and even larger vehicles. Sometimes simply having something to reduce the impact of the wind on your car can make your alarm much less likely to go off.
Prioritize OEMs and Reputable Dealers
OEMs are usually the more expensive option, but considering that low-quality installations do more harm than good, they tend to be the better choice.
That said, many good aftermarket dealers will still give you good-quality installations. Some aftermarket options even have extensive features you’d be hard-pressed to find in OEMs.
So it’s important to research properly and find a good middle ground between price and quality.
Adjust Your Sensors
Motion sensors on your car are meant to detect movement within a certain range. If you have a private garage, this usually isn’t a problem unless you have an overly curious cat or dog. However, if you park your car on or close to the street, sensitive sensors can be a problem.
Some cars now ship with adjustable motion and shock sensors. This addition allows you to reduce the sensitivity of your sensors so they only trigger when too close to your car. Of course, not every car will have this, especially if you have an older model.
In Short About How Car Alarms Work
While knowing the most common things that can trigger a car alarm is great knowledge, truly knowing how car alarms work will allow you to maximize the protection of a car’s security system.
The first step to do this is to stop thinking of your alarm as the entirety of the security system. While car alarms may have started out like that, they’ve come a long way since then.
Today, most cars feature a comprehensive security system designed to keep your car extremely safe. Here’s how each major part of the system works:
Control Unit
The control unit acts as the “brain” of the security system. Essentially, its main job is to direct activity to or from the different parts of the system.
For example, when a motion sensor detects movement, it first “tells” the control unit. The control unit then closes the switch to the alarm, which triggers it.
Sensors
While the actual alarm seems to be the most useful, the sensor is what does most of the heavy lifting. Sensors act as the eyes and ears of the car. They allow it to detect movement, broken windows, voltage drops, and sometimes, even loud enough sounds.
If your car alarm keeps going off, it most likely has something directly to do with the sensors. Most times, there’s either something triggering the sensor or it’s faulty.
Types of sensors:
- Door sensors
- Trunk Sensors
- Motion Sensors
- Shock Sensors
- Voltage Sensors
Siren/ Alarm
The sirens or alarms are the final part of any car’s security system and, to most, are the most crucial. While most of the work done by the control unit and sensors goes a bit under the radar, the alarm is what actually alerts you to a potential intruder.
Conclusion
Car alarms almost always activate as a result of a triggered sensor. These sensors can detect pressure, voltage, and even movement, allowing them to protect your car from a variety of threats.