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Why Does Alarm Goes Off When Changing Battery?

If you’ve just changed your car’s battery and your car alarm goes off suddenly. It can be pretty frustrating when dealing with those car problems and their repairs. However, it can get even more frustrating when you don’t know the reason behind the issue of the alarm goes off when changing battery.

We know how annoying and stressful this problem can be for car owners. In fact, this issue can be more irritating if it happens in the middle of the night! However, even though there’s no threat coming from burglars, this sort of problem can be due to some serious underlying issues. That’s why you should know about these underlying issues and if they need your immediate attention. In this article, we’ll discuss the issue of a car alarm going off in detail.

How Does A Car Alarm System work?

Before we start diving into all the potential reasons your car alarm goes off when changing battery unexpectedly, you need to have a basic understanding of how these alarms work in the first place. There are multiple generation car alarms, but they all have some or all these features. Every car alarm out there connects to your door and trunk sensors. This helps because if someone up to no good picks the lock, smashes out the window in order to unlock the car), or simply opens the door or trunk by any other means, you want the alarm to let others around know that something is wrong.

When you unlock the car with a key fob, it disables the alarm. But if any thief manages to get the car unlocked without a key fob, it can set off the alarm. It’s also why the alarm goes off if you lock the vehicle from the outside and someone inside the car unlocks it and gets out! Another sensor alarm systems use to set off the alarm are shock sensors. Not every car has a shock sensor, but if your vehicle has one, then it can help prevent some car thefts. Shock sensors work by detecting impacts to your car.

This can happen when someone runs into your car or when someone smashes out a window. This matters because with a traditional car alarm system, they can smash the window and take out whatever they want. As long as they don’t open the door, the alarm won’t go off! Shock sensors give you an extra layer of protection. They can also go off if someone is in the process of picking the lock on your car. It’s nice to have the alarm go off before anyone even tries to get in!

Reasons Behind Alarm Goes Off When Changing Battery?

There are more than a few reasons your car alarm might be going off more than it should. Below we’ve highlighted seven reasons your alarm might be acting up.

1. Key Fob Malfunction:-

key fob

One of the most common reasons for a car alarm that keeps going off is a malfunctioning key fob. The key fob is a manual way to set off the alarm, so if there’s something wrong with it, then it can easily set off the alarm when you don’t want it to. If you suspect the key fob might be the problem, try replacing the key fob battery and see if the alarm keeps going off.

2. Wiring Issue:-

damaged wiring

Everything in your car alarm uses electricity, and all that electricity runs through wires. When everything is working as it should, there aren’t any problems. But if some of those wires get damaged, start to cross, and electricity goes to the wrong place, then your car alarm goes off when changing battery. Wiring problems are tricky to track down, but if you can find the fault, they’re usually pretty straightforward to fix.

3. Over Sensitive Sensors:-

alarm shock sensor

In addition to door and trunk sensors, your vehicle can use shock sensors to set off the alarm. These sensors have various sensitivity levels to trigger an alarm. The most sensitive sensors out there will go off if even a cat brushes up against it. If you have overly sensitive shock sensors, you might be able to adjust them yourself, or you might need to take them to a dealership.

4. Faulty Control Unit:-

car alarm control unit

Every sensor that’s a part of your vehicle’s alarm system reports to an alarm control unit. While it’s rare for these units to act up, it’s not impossible. If you’ve ruled out all the sensors and you’re sure the right voltage reaches the control unit, the unit itself might be your problem.

5. Incorrect Installation

faulty car alarm installation

If you  there’s a good chance something’s not hooked up correctly. It can be as simple as a crossed line or a missed sensor. Double-check the installation process or take it back to the installers.

6. Blocked Or Damaged Sensors:-

car alarm door sensor

Your car alarm uses various sensors to alert you of a problem. So, it makes sense that if some of those sensors aren’t working the way they should that your car alarm might keep going off.

What To Do If Your Car Alarm Goes Off Suddenly?

If your car alarm goes off after replacing the battery, here are a few ways you can troubleshoot your alarm:

Step 1:- Try To Unlock Your Car

First, try to unlock the car manually, using a physical key instead of a fob. That may solve your problem.

Step 2:- Try To Disconnect And Reconnect The Battery

If it doesn’t, you should try to disconnect the car’s battery and then reconnect it.

car alarm keeps going off

Step 3:- Refer To Your Car’s Owner’s Manual

You can turn off the alarm by finding your vehicle’s alarm transmitter system. There’ll be a switch to turn your car on and off. If you don’t know where to look, refer to your car’s owner’s manual.

Step 4:- Visit A Mechanic

If you’re still having problems with your alarm, consider bringing your vehicle to a mechanic.


We hope the above-mentioned information about the issue of alarm goes off when changing battery will be helpful to all the readers. If anybody’s doubts persist feel free to comment in the comment section below. We’ll try to solve your doubts as soon as possible.