How to Repair a Car Alarm

How to Repair a Car Alarm

An alarm that is not working as expected and keeps going off by itself can be a nuisance. A malfunctioning alarm puts your car in danger of being stolen or being damaged by vandals. Credible car alarm manufacturers have an anti-theft option available in case your alarm fails. The bad news about alarms is that like any other car component; they too need repairs. I have come up with steps that will guide you on what to do when your car alarm goes off without a trigger.


Resetting the Alarm Remote

One of the reasons why an alarm would go off is a failing key fob. The key fob may have failing batteries or is broken and cannot send signals to the car alarm system. To sort out the key fob issue, you may have to

  • Read the Remote Manual to be able to understand the troubleshooting procedures highlighted there.
  • Use an OBD2 scanner to reset the entire alarm system.


Resetting the Alarm System

If the key fob seems to be functioning well, but the alarm still won’t go off, then you can try the following less complicated process to turn off the alarm.

1. Unlock the Car

Inserting the key to the door and trying to lock or unlock the door manually may shut down the alarm.

2. Start the Car

Put the vehicle in drive mode and make an attempt to drive and see if the alarm goes off.

3. Turn the Key to the Door Twice

This is better done on the driver side door. You insert the key and make an attempt to turn the key in the lock and unlock position twice in quick succession.

4. Hold the Key in the Unlocked Position

Another alternative is holding the key for at least two to three seconds in the unlock position to try and silence the alarm.


Disconnecting the Battery

The idea behind disconnecting the battery from its terminals is to reset the car and see if the alarm will also be reset. You can achieve this is three easy steps

1. Disconnect the Negative Terminal

Use a wrench to loosen and pull out the negative terminal wire from the battery. This will disconnect all the electrical components of the vehicle and shut off the alarm briefly.

2. Re-attach the Wire

After two or three minutes, you can re-attach the negative terminal wire back to its position. Doing this is supposed to clear all the electrical presets and it will take a few minutes to recalibrate.


Replacing The Alarm Fuse

Your alarm may be going off intermittently because of a bad fuse. There is a dedicated fuse for your car’s alarm system. The fuse is commonly found under the steering wheel. First of all, you need to consult your owner’s manual to be sure of what fuse you need to remove and replace.


Disabling the Alarm

When you have no other alternative or all the above methods have failed, you will have to think of disabling the alarm. Disabling the alarm may have many other consequences such as your cat not being able to start because the alarm system is connected to the ignition system. Before carrying out this procedure make sure you know what you are doing or consult a qualified mechanic to do it for you in the best possible way. An alarm is considered disabled by disconnecting the wires connected to the alarm siren.



An alarm is a security feature that should deter any criminals from inflicting further damage to your car or even stealing it. Though the persistent noise may be annoying, you should not overlook its importance. Make sure that you take the car to your trusted mechanic who will take appropriate steps to repair or turn off the car alarm without compromising security.

How to Repair a Car Alarm
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How to Repair a Car Alarm
I have come up with steps that will guide you on what to do when your car alarm goes off without a trigger.
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Chief editor at Paul's Gigantic Garage. I came up with this blog to help you to sort out some basic problems your car may be facing and in turn, save lots of cash by some of my DIY tips that I hope will get your car out of its current situation. I also had in mind motor enthusiasts who for the love of cars who are constantly looking for information about cars on the latest trends, questions, fixes, driving, tricks, and accessories.