When functioning properly, car alarms are powerful enough to repel thieves who try to steal your car. However, if the alarm is broken, the sound of the alarm can disturb the people around. If your car alarm goes off, there are several ways to turn it off or reset the controller computer. Start with the easiest and fastest way, and move on to more complicated methods if it doesn't work.
Step
Method 1 of 3: Using a Key and Key Fob
Step 1. Use the car key to open the driver's door
Many car alarms are designed to go off on their own when the owner uses a key or key fob (a kind of token to remotely control keys and car alarms). The alarm may go off if you insert the key into the driver's door lock, lock the door, and then open it again. Since the car is locked with the correct key, the alarm will receive a signal to turn off the siren.
- Sometimes you can use the passenger door, but we recommend using the driver door just to be sure.
- If the door is locked, simply unlock it again. If the alarm hasn't gone off, try locking the car door and opening it again.
Step 2. Use the key fob to lock and unlock the door
The principle is the same as using a car door lock. Most car alarms will go off when the car key is opened with the key fob. Stand near your car, press the lock button, then press the unlock button. Usually the car alarm will go off when the key is opened with the appropriate key or key fob.
- If the car door lock does not respond, the key fob battery may be dead. Replace the device battery and try again.
- If the car door locks open but the alarm doesn't go off, you may need professional repair.
Step 3. Make sure you haven't hit the panic button
Most key fobs have what is known as a “panic button”. This button activates something similar to a car alarm. The horn will squeak and the light will come on. If you accidentally press the panic button, the alarm will continue sounding until you press this button again. On some cars, you can turn off the panic button by starting the car and starting to drive.
- Most panic alarms will go off on their own if you wait.
- The panic alarm may not go off when the car is started, but it will turn off when the car starts.
Step 4. Start the car
Your alarm is designed to prevent the vehicle from being stolen from someone who doesn't have a key. So, usually enough alarms can be turned off simply by starting the car using the ignition key (ignition). Unlock the door and get in your car. Insert the key into the ignition slot and turn it to “ACC” (short for accessories which means accessory). If the alarm is still on, try starting the car. Remember, some alarms cannot be turned off just by starting the car, even using the car key itself.
The alarm should be reset when the ignition key is turned. However, sometimes this method does not work
Step 5. Read the user manual
Don't let the loud squealing car alarm you can't handle because you don't want to read the manual. Instructions on how to turn off this alarm may be in the manual. If everything else doesn't work, try checking your car's user manual to find out the next steps.
- Every car manufacturer uses a different car alarm so there may be different ways to turn it off.
- You may need to repeat certain actions several times to reset your computer, such as locking and unlocking car doors.
Method 2 of 3: Removing the Alarm Fuse
Step 1. Find the right fuse box
Most modern cars have more than one fuse box located in the vehicle for various electrical components. Use the vehicle manual to identify the box containing the fuse that powers your car alarm. The fuse box may be in the engine compartment or car cabin. If it's in a cab, you may need to remove the trim to gain access to it.
- Be careful when removing your car's interior plastic trim as it may be brittle and break easily.
- Set aside the trim in a safe place so you don't step on it or sit it on while you work.
Step 2. Identify the car alarm fuse
Many fuse boxes have a diagram on the underside of the cover. If not, check the vehicle's user manual. Find the fuse in the diagram that powers the car alarm, then locate the fuse in your vehicle. If there is no diagram on the fuse box cover or the user manual, you can only use the "guess" method in the next step.
- You may be able to find a fuse box diagram online.
- The fuse box diagram may be in your vehicle repair manual, if you have one.
Step 3. Remove the fuse with pliers
Once you've found the right fuse, use sharp-edged pliers or specially designed plastic clips to pull the fuse out of its place in the box. The car alarm should go off as soon as the fuse is blown. If you can't pinpoint the exact fuse location even with the help of a diagram, remove and reinstall the fuses one by one to find out which fuse can turn off the car alarm.
- The alarm will go off when the proper fuse is removed from the circuit.
- Some car alarm manufacturers don't put a fuse in a fuse box.
Step 4. Replace the fuse and see if the alarm comes back on
When the car alarm has stopped, use pliers or tongs to slide the fuse back into place. Supposedly, the car alarm has been reset and does not come back on after being put back in the fuse box. If the alarm comes back on, it means your alarm is not working properly.
- If the alarm comes back on, it looks like the car needs professional repair.
- If the alarm goes off a few minutes after you re-insert the fuse, it means that something has triggered it, such as a key fob error or a fault in the electronic control unit in the vehicle.
Method 3 of 3: Disconnecting the Battery
Step 1. Wear a good safety device
Before handling your vehicle, be sure to wear proper safety gear. Since sparks can spark when handling car batteries, wear safety glasses or other eye protection before disconnecting them. It's also a good idea to wear protective gloves as the engine case can get hot. In addition, the gloves will protect against pinching and cuts.
- Always wear eye protection when working on your vehicle, especially when handling electrical components.
- Gloves can protect hands from pinching, scratching, and heat from the engine case.
Step 2. Find the car battery
You can find car batteries under the hood, but some car manufacturers prefer to put them in the trunk to save space and improve weight distribution. If the battery is in the trunk, it may be under the piece of carpeted wood that separates it from the luggage compartment and is located along the spare tire.
- If you have trouble locating the battery, consult your vehicle's user manual to find it.
- There may be a protective cover on the battery in the engine case that needs to be removed so that the battery can be seen.
Step 3. Disconnect the grounding wire from the negative terminal
You can identify the negative terminal by following the thick black wire that runs down the body of the car or look for the word “NEG” or the (-) symbol above one of the battery terminals. The bolts don't need to be completely unscrewed, just loosen them so the wires can slide out of the terminals. The alarm along with all other electrical components in the car should be off by now.
- Secure the ground wire along with the battery to make sure it doesn't accidentally touch the negative terminal again.
- You do not need to disconnect the positive cable from the battery.
Step 4. Disconnect all alarm backup batteries
Some car alarms are equipped with a small backup battery that will power the alarm if it is not connected to the car battery. This battery is not designed to power alarms, horns and lights for extended periods of time. Its main role is to keep the alarm working while you work on the vehicle so that you don't have to reset everything when the main battery of the car is reconnected. Refer to the car or vehicle alarm system user manual to locate and disconnect the spare battery.
- Most factory alarms do not come with a backup battery.
- If you can't find a spare battery, the alarm will eventually go off if the main battery isn't connected for too long.
Step 5. Wait for the computer to finish resetting
Depending on the vehicle type, the amount of reset time required may vary. You may need to wait up to an hour to make sure the alarm and the vehicle's ECU (Electronic Control Unit) have been forced to reset due to a lack of power.
Forcibly resetting the computer will cause the radio and clock settings on the vehicle to be erased
Step 6. Reconnect the battery
After waiting for about an hour, reconnect the ground wire to the negative battery terminal. Tighten the bolts to secure the wires to the terminals and make sure they are not wobbly or loose. If this cable comes loose while you are driving, the car will suddenly turn off. The alarm should not sound when you reconnect the battery. If so, the vehicle needs to be checked by a professional.
- Make sure the battery cable is securely attached and return any covers that were previously removed to access the battery.
- Start the car to make sure there are no further disturbances.
