A well-functioning car alarm is a great way to deter criminals from stealing your car. When they don't work properly, they can make you very embarrassed. If your car alarm starts to sound, there are a number of ways to turn it off or restart the computer that controls it. Start with the quickest and easiest methods available to you, then try more complex options if necessary.
Method 1 of 3: Use your keys or keychain
Step 1. Use the key to lock and unlock the driver's side door
Many factory car alarms are designed to go off when in close proximity to the proper key or fob. You could turn off the car alarm simply by inserting the key into the driver's door lock, locking and unlocking it. Unlocking the car with the right key could signal the alarm that it can now be turned off.
- While unlocking the passenger side door might work, it is more likely to work with the driver's door.
- If the door is already locked, you just have to remove it. If the alarm does not go off, re-lock it and then remove it.
Step 2. Use the key ring to lock and unlock the door
To use a similar method to the key, you can unlock the car doors with the key fob, which will also turn off the factory alarms in many cars. Stand close enough to the vehicle for the key fob to reach the required range, then press the button to lock it, then remove it. Many car alarms will go off when you unlock the doors, either with the keys or the appropriate fob.
- If the door lock does not respond, the key fob may have run out of batteries. Change them and try again.
- If you unlock the doors, but the alarm continues to sound, you may need to have your car repaired by a professional.
Step 3. Make sure you haven't pressed the panic button
Most keychains have an orange or yellow button that is commonly referred to as the "panic button." This button is activated in much the same way as a car alarm. The horn will sound and the lights will blink. If you accidentally press the panic button, the effect will continue until you press it again. In some cars, you may disable panic mode by starting the car and driving it.
- Most panic alarms will go off on their own after a while.
- Maybe the panic alarm doesn't go off when you start the car, but when you start driving it.
Step 4. Start the car
The alarm is designed to prevent someone from stealing your car without a key, so starting the car with the correct key is often enough to turn it off. Unlock the door, open it, and enter the vehicle. Insert the key and turn it until you reach "ACC" (accessories). If the alarm doesn't go off, try starting the car. Remember that some of the auto aftermarket alarms may not allow you to start the car while the alarm is sounding, even with the correct key.
Turning the ignition key will turn off the alarm, but not always
Step 5. Read the owner's manual
Standing next to a car with a blaring alarm couldn't be considered the best time to do some reading; however, your vehicle owner's manual will likely provide you with important information on how to turn off the alarm. If you can't turn off the alarm with your keys or fob, check your owner's manual for instructions.
- All automakers use different types of alarms, so some may require you to take specific steps to turn them off.
- You may have to repeat an action several times in order to restart your computer, for example locking and unlocking the door.
Method 2 of 3: Remove the alarm fuse
Step 1. Find the correct fuse box
Most modern vehicles have more than one fuse box inside, which serve various electronic components. Use your vehicle owner's manual to identify the box with your car's factory alarm fuse. The fuse box could be located in the engine compartment or in the cab of the vehicle. If it is in the cockpit, you may have to remove some special parts to gain access to it.
- Be careful if you are removing the plastic trim from inside the car, as they could be brittle and prone to breaking.
- Set the trim pieces aside to avoid stepping on or sitting on them while you work.
Step 2. Identify the car alarm fuse
Many fuse boxes will have a diagram on the bottom of the cover. If you can't find it, check your vehicle's owner's manual. On the diagram, identify the fuse that operates the alarm, then find the one inside the vehicle. If you can't find the diagram on the cover or in the manual, you'll have to use the "guess and check" method to locate it.
- You may be able to find a diagram of the fuse box online if there are none in the car.
- You can also find this diagram in your vehicle's repair manual, if you have one.
Step 3. Pull out the fuse with pliers
Once you've found the correct fuse, use a pair of pointed pliers or plastic pliers designed to pull the fuses out of the box. The alarm should go off immediately if you pull the correct fuse. If you can't identify the correct fuse in the diagram, remove and replace the fuses one by one until you remove the one that will make the alarm stop.
- The alarm will go off immediately when you remove the correct fuse.
- Some replacement alarms may not have a specific fuse in the box.
Step 4. Replace the fuse and see if it starts beeping again
Use the pliers or tweezers to slide the fuse back into place after the alarm has gone off. The alarm will reset and will not sound again once you have replaced the fuse in the box. If the alarm sounds again while you slide the new fuse into place, then this means that the alarm is not working properly.
- If the alarm goes off again, you may need to take the vehicle to a professional for repair.
- If the alarm sounds again a few minutes after the fuse was reinserted, something must have caused it to go off, such as a faulty key fob or a problem with the vehicle's electronic control unit.
Method 3 of 3: Disconnect the Battery
Step 1. Put on the proper safety gear
Before making any repairs to your car, you should make sure you put on the correct safety gear. Because there is a risk of sparks when working with a car battery, wear safety glasses or other form of eye protection before attempting to disconnect it. You may also need to wear gloves to protect your hands from the heat in the engine compartment, as well as from nicks and cuts.
- You should always wear eye protection when servicing your vehicle, especially if you are handling electrical components.
- Gloves can protect your hands from being pinched, scratched, and from the heat in the engine compartment.
Step 2. Find the battery
Typically, your vehicle's battery will be located under the hood of the engine compartment, but some automakers place it in the trunk to save space or improve weight distribution. When a battery is in the trunk of a vehicle, it is often found under an upholstered piece of wood that separates it from the trunk compartment and may be next to the spare tire.
- If you have difficulty locating the battery, check your user manual.
- The battery may have a protective cover in the engine compartment, which you will need to remove in order to find it.
Step 3. Disconnect the ground wire from the negative terminal
You can identify the negative terminal by following the thick black wire that connects it to the body of the car or by looking for the letters "NEG" or the symbol (-) above one of the two battery terminals. Use a wrench or pliers to loosen the nut that secures the black ground wire to the negative battery terminal. You don't need to remove the nut completely, just loosen it enough to slide the wire out of the terminal. The alarm will go off immediately, as will all other electronic components in the car.
- Tuck the ground wire next to the battery to make sure it doesn't accidentally come back into contact with the negative terminal.
- You don't have to remove the positive battery cable.
Step 4. Disconnect any backup batteries from the alarm
Some aftermarket car alarms come equipped with a small backup battery that will keep the alarm going after your car battery has been disconnected. These batteries are not designed to power the alarm, horns, and lights for long. Its main function is to keep the alarm in operational condition while you work on your vehicle, so you won't have to reset anything when you reconnect the vehicle's main battery. Consult your owner's manual for information on your alarm system, or check your vehicle's owner's manual for the backup batteries installed. This will also allow you to locate and disconnect the backup battery.
- Most factory alarms are not equipped with a battery backup.
- If you can't locate the backup battery, it will eventually turn off if you disconnect it from the main battery for too long.
Step 5. Wait until the computer restarts
The time it takes for the computer to restart can vary greatly depending on the vehicle. It may be best to leave the vehicle unplugged for an hour to ensure that the alarm and the vehicle's electronic control unit (ECU) are forced to reset due to a lack of power.
Forcing the computer to restart will also cause preset radio stations to be lost and you will have to reset the clock in your vehicle
Step 6. Reconnect the battery
After about an hour, reconnect the ground wire to the negative battery terminal. Tighten the nut that holds the wire to the terminal and check to make sure it is not loose. If the cable becomes disconnected while driving, the car could stall. The alarm should not sound while you reconnect the battery. If it does, you will need to take your vehicle to a professional to have it repaired.
- Make sure the battery cables are secure and replace any covers you removed before accessing the battery.
- Start the car to make sure there are no other problems.