Why Does My Car Alarm Keep Going Off – Here Are the Top Reasons and How to Solve It

Why does my car alarm keep going off – a common question car owners would ask the moment they hear the annoying false alarm from their vehicles. For city-dwellers especially, there are few things more maddenіng than blarіng – and nearly always false – audіble car alarms.

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AAA cities research that 99 out of 100 times a car alarm goes off, іt's from some cause other than a thief trying to make off wіth your ride. False alarms can be caused by a passing garbage truck, a thunderclap or a neighborhood cat jumping on the hood. For recurrent car alarm disruptions, anti-noise ordinances may offer some relief.

Car alarms that won’t quit can cause the distraction in the neighborhood and can be quite embarrassing. We have listed below the common causes why your car alarm keeps going off and the simple ways to fix them:

1. Alarm Remote or Key Fob Not Working

Via caranddriver.com

A key fob is an important accessory for providing a secured access to your vehicle. The device is used to unlock doors and jumpstart your vehicle’s ignition system.

However, a faulty key fob or alarm remote cannot send a proper signal to your car’s alarm system, causing it to go off

How to fix:

Dealing a faulty key fob may vary depending on your car model, so the best thing to do is to consult your manual and read the section on how to reset your alarm remote.

Most manuals might suggest you replace the fob battery. For the latest car models, you may also use a code reader/scanner to reset your alarm remote.

Materials needed:

  • Code reader/scanner (in this video, we used the ANCEL AD310 Classic Enhanced Universal OBD II Scanner Car model)

Please check the video below on how to use the code reader/scanner:


2. Dirty Hood Latch Sensor

Via honda-tech.com

One of the common causes why your car alarm won’t quit is a dirty hood latch sensor. This device is part of the system design that protects your car from damage, thefts, and even accidental opening of the hood.

The hood latch sensor can often trigger false alarm due to engine grease and road grime.

How to fix:

As mentioned above, a hood latch sensor covered with grease and dirt can create false positive and may trigger the alarm. What you can do first is to locate the sensor and check if it is dirty. Try cleaning it with a brake cleaner and see if it works.

Materials needed:

  • Brake cleaner

Steps in Cleaning the Hood Latch Sensor:

Step 1: Locate the latch sensor inside the hood.

Step 2: Unplug the sensor carefully (make sure you have disconnected the battery ground cable).

Step 3: Spray the brake cleaner on the sensor until all the grease and contaminants are removed.

Step 4: Brush the parts to further remove any leftovers.

Step 5: Wash and wipe it dry using a microfiber towel.

Step 6: Re-install the hood latch sensor. Connect the electrical connector and make necessary adjustments on the hood latch bolts.

Step 7: Lower the hood and check the operation.


3. Bad Hood Latch Connection

If cleaning the hood latch sensor won’t solve the problem, then the culprit might be a bad hood latch connection due to a faulty sensor. This means your car alarm can be falsely triggered because the sensor is not able to respond properly.

A faulty sensor can also falsely trigger the control unit, causing your car to misbehave (check this post why is my airbag light on).

How to fix:

The first thing you can do is to open your hood and locate the hood latch sensor. You can most likely find it near the headlights in a form of a little plunger with a wire. Once you find it, try disconnecting it and check if it solves the problem.

You may also check this video on how to disconnect the hood latch sensor:


4. Low Battery Levels

Via used-auto-parts-online.com

Car alarms are designed to detect low battery levels so that you can be informed if you need to replace it or not. Trying to start your vehicle with a dying battery can cause your car alarm to keep going off.

The best thing you can do is to check first if it is in good shape or not.

How to fix:

First, try to measure the voltage levels of the battery using a voltmeter. The desired battery voltage reading should be around 12.6 Volts. If it is lower, then your battery might need a replacement.

You may also be interested to check out this article on how to check the car battery for more details.


5. Corroded Battery Terminals

Via wikimedia.org

Corroded terminals of your battery can also falsely trigger the car alarm system. It can often lead to premature failure or even cause the charging system to stress down.

The corroded terminals can lead to poor connections and may be falsely interpreted as a low battery signal, causing your car alarm to not shut off.

How to fix:

Open the location of your batteries and check the terminals. If they are corroded and covered with grime, remove the batteries and try cleaning them using a battery cleaner.

Don’t forget to wear protective gloves before removing the batteries! After cleaning, return the batteries and see if the issue has been solved.

Please see this article to get more detail about how to deal with car battery corrosion.


Conclusion!

Car alarms that won’t quit is truly an embarrassing situation. There are many reasons why your car alarm keep going off for no apparent reasons. In this post, we showed you the basic on how to resolve the problem immediately. With the right knowledge and tools, you are assured to fix faulty alarms without the need of a professional mechanic.

Have you enjoyed the information shared on this post? If you liked it, I recommend that you share this with everyone you know so that they will be advised what to do on a car that won’t quit.

Do you have suggestions and comments? Don’t forget to share them in the comment section below!

About the Author Alice Brown

I am just a car girl. Simply interested in the automotive and vehicular world. I started out as an apprentice mechanic working at my father’s garage. I'm hoping my two cents will help you fix a blinking light on the dashboard or that cranking noise that you don’t seem to know where it is coming from.