Why do vehicle Alarms Stop Working When the vehicle is being Unlocked With a Key?

Vehicle alarms are effective at preventing theft and warn owners when their vehicles are being tampered with. However, it can be a noisy and annoying feature when it goes off for no apparent reason. As a vehicle owner, there is a good probability that at one time or the other, the vehicle’s alarm is triggered without any obvious reason.

What triggers a vehicle alarm when the vehicle is being opened, knowing fully that the alarm is there to protect the vehicle from thieves? This article examines various reasons why an alarm can go off when opening the vehicle with a key. Although a common issue, it is simple to fix.

An alarm may repeatedly sound due to various factors reasons, including defective sensors, a damaged key fob, a low battery as well as wiring problems. If the vehicle doors are not properly closed, it could be another potential cause. While most problems may be resolved by resetting the alarm or Electric Circuit Unit (ECU), other cases may need to be overseen by a professional.

How Car Alarms Work?

The fundamental structure of all feasible vehicle security configurations is the same.

Sensors located throughout the vehicle and the receiver provide data to a computer, which can be the vehicle’s ECU or a different unit for alarm systems only. The receiver reacts to radio signals sent by a remote key fob, instructing the vehicle’s battery-operated loudspeaker to play the alarm sound when it detects a threat.

In the event that a thief cuts the battery wires for a stealth operation, the security setup is usually made to have a source of backup power.

Simple alarms detect a significant reduction in voltage, including scenarios when the vehicle’s door is opened, or an electronic attachment between a vehicle and its trailer is severed. Then, the computer reacts.

Why Does My Car Alarm Go Off When Unlocking With a Key?

The loud noise produced by vehicle alarms is intended to scare away thieves and notify the vehicle owner of the attempted act. Vehicle alarms usually act as a preventive measure for theft. However, on certain occasions, the alarm may be triggered even when there has been no attempt to break in.

A computer, multiple sensors, a receiver tuned to the vehicle’s key code as well, and a loudspeaker that is tuned to your key code are all components that make up the alarm system in recent vehicles. When a sensor or more than one sensor detects an action, like the vehicle moving with its engine off, a loud sound, or an object falling on the vehicle or close to it, the alarm will be triggered.

A sensor, upon receiving a reaction causes, triggers the alarm, and it continues to sound until someone turns it off or a reset is done. Although the vehicle alarm is active and running in a vehicle, it will not be triggered until something unexpected happens.

Why do vehicle Alarms Stop Working When the vehicle is being Unlocked With a Key?

Reasons Why a Vehicle Alarm Goes Off Repeatedly

1. Faulty Key Fob

A little plastic controller called a key fob is what keyless entry systems use. A short-distance radio transmitter built into this tiny gadget transmits a separate signal to the receiver inside the vehicle. When working properly, this controller makes it simple to kick-start the vehicle while locking or unlocking the doors with the push of a button. However, if it were faulty, it would fail to correctly transmit the signal to the vehicle’s receiver, which would trigger the alarm for no obvious reason.

Batteries in key fobs can run out after long usage; in such cases, a new battery should fix the issue. They must occasionally be reset as well. Open up the key fob and find crooked buttons or damaged contacts if your car alarm keeps going off in the middle of the night and you feel anything is wrong with it. If all of these connections are correct, it may become necessary to either reprogram such controller with or without a professional’s assistance or scan it using a code reader.

2. Defective Bonnet Latch Sensor

Asides from a controller that is not working properly, various sensors in the vehicle could trigger the alarm at random. The hood/bonnet latch sensor is made up of a basic electrical switch that detects whether the hood is open is an example of this. A functional hood sensor detects when the hood latch is not closed and turns on the warning light in the dash. However, with a broken hood sensor, the vehicle alarm will be triggered, regardless of the time of day or whether being driven or not.

A defective hood sensor can be caused by a number of things, but dirt is by far the biggest. The sensor usually gathers dirt, particles as well as engine grease because it is usually located inside the engine bay over the frame of the headlight. As a result, it frequently malfunctions and sets off false alarms. In addition to preventing erroneous alarms, keeping both the sensor and

hood latch clean also shields the vehicle from destruction and theft. A hood latch sensor may be cleaned with a regular brake cleaner and cleaning brush. After cleaning, if the alarm still sounds, there may be a problem with a sensor, or it may have been tampered with. Replace it immediately in such an instance.

3. Bad Hood Latch wirings

In some instances, even after replacing or cleaning the hood latch sensor, the alarm may still sound. When this occurs, take a closer look at the hood latch connection. Despite the fact that problems of this nature are uncommon, they should not be ignored. A broken hood latch can cause false alarms, have a negative effect on the control unit of the vehicle, and result in improper orders and readings, like turning on the airbag warning light when nothing is wrong with the airbag.

Disconnecting and connecting back hood latch wirings usually solves the problem if there are no visible symptoms of damage. If not, check the latch connection for wear, damage to thr latch, misalignment, cable binding or fraying, condition of the pull lever assembly, and rubber stop position. Verify the springs and levers for wear and damage. It should cost about $240, which includes labor fees to fix this issue.

4. Bad Door Lock Sensor

An alarm may also go off as a result of the door lock sensor. The door lock actuator typically houses this sensor, which typically has two wires attached (an open circuit and a closed circuit.) Due to how it is built, door lock sensors are frequently anticipated to react negatively in wet conditions when water finds its way into the actuator connector. Normal use eventually leads to the internal wiring of the device failing as well. The release wire bracket on the actuator is prone to breaking on certain vehicle brands and models.

Fixing the problem involves finding the source of the leak and sealing the connector with protective grease. Use door switches or the key fob to check if the door lock actuator is working properly, and listening for any accompanying humming or buzzing sounds when the switch is pressed aids in identifying the issue. A scanner can help in identifying the vehicle door primarily responsible for triggering the alarm repeatedly. Check the actuator and door lock connector and actuator of whichever door is open to see whether they need to be replaced.

5. Reduced Battery Level.

There is definitely a problem with a vehicle’s battery if the vehicle alarm inexplicably goes off at midnight and one wakes up to a battery dead. The battery is not only dead, but it is also the cause of the annoying anti-theft warning. Unknown to some vehicle owners, vehicle alarms also primarily help to alert the driver when the battery is getting low. Therefore, starting a vehicle with a dead battery will immediately trigger the alarm.

Therefore, do not fear the next time an alarm goes off when a vehicle is started. Check the operating voltage using a voltmeter. It may become necessary to shock the battery or have it completely changed if it reads below 12.6V (or any voltage recommended in the owner’s manual).

6. Super Sensitive or Weak Sensor Connection

The types of movement and shock sensors vary among vehicles. For instance, older vehicles usually contain two sensor types: a shock and a door sensor. On the other hand, contemporary vehicles would have more. While modern sensor types may be changeable, the older ones usually have preset settings. Similarly to that, having an aftermarket or brand-new alarm system affects sensor sensitivity. Volkswagen and Audi vehicles are ideal illustrations of how a vehicle’s sensor sensitivity fluctuates since they are popular for having excessively sensitive factory-made sensors.

No matter how many or sensitive the sensors are in a vehicle, their connection to one another is a solid fact. An alarm will undoubtedly sound if even one of the microphone sensors, shock sensors, door sensors, proximity sensors, tilt sensors, or glass-break sensors is on. It is essential to verify that a tight electrical connection exists among all sensors because they are powered by the primary battery. Take the vehicle to a nearby auto shop to have the alarm inspected by a professional if one has no idea of what to check.

7. Wiring Problems or Disconnected Circuitry

Another issue that requires investigation when an alarm keeps going off is wiring, which relates to sensors that are too sensitive. Sometimes, the issue is not with the battery, key fob, or sensors. Instead, a section of the electrical cable connecting these parts could be damaged or loose.

Find associated symptoms to confirm if this is the cause of the problem. If the alarm goes off repeatedly with the horn and headlights also flashing, it might be a wiring issue. Otherwise, another source could be the alarm’s trigger.

8. Poorly fixed Alarm System

Factory-fitted alarm systems do not offer more than a minimal degree of anti-theft protection and security. The main justification for why most vehicle owners choose an aftermarket security system is the thin layer of protection it offers. The drawback is that aftermarket vehicle alarms are frequently installed incorrectly, particularly when done in a home space or garage. If an alarm keeps going off at night, that is a clear indication that the vehicle security system was set up improperly.

Check the installation manual again for directives if the vehicle alarm system was installed without help. However, if a professional mechanic did it, check back on the auto repair shop and narrate the situation. The nighttime noises from the vehicle typically stop once the alarm system is reinstalled.

How to Solve Problems of a Vehicle’s Alarm Going off Repeatedly Due to Certain Reasons

If one is wondering why a vehicle’s alarm is going off when unlocked with its key, a few answers have been provided in this article for everyone. There are several factors that could trigger an alarm when using a key to unlock the vehicle’s door.

1. Sensitive Sensors Fix

Fixing extra sensitive vehicle alarm sensors does not require a trip to an auto shop. As a matter of fact, by simply going through the owner’s manual, by following instructions, one can find the vehicle’s alarm and reset its sensors. Once this is successfully done, the vehicle alarm has been reset not to be too sensitive and does not go off when simply trying to open the doors.

2. Damaged Key Fob Fix

To solve this problem, a battery replacement may be the only thing to be done to the key fob. If, after doing this, there is no significant improvement, then the key fob needs a total reconfiguration or reset.

3. Locked The Vehicle Using a Remote Key Fix

The simplest way to fix this issue is to use the remote key to unlock the vehicle every time rather than using the key directly. However, if the alarm is mistakenly turned off while unlocking using a key, just turn the key over in the ignition space. Immediately the vehicle recognizes the key; the alarm is deactivated.

4. Car Battery requires Charging Fix

Find out the charge of the vehicle’s battery with a voltmeter. If the voltage on it is not enough, a battery recharge becomes essential. If there is a case of a dirty battery, it can be cleaned using a battery cleaner. Just ensure to be adequately protected by wearing protective clothing.

If a vehicle’s battery is seriously corroded or damaged, it becomes necessary to replace it. Once the battery is in good and proper working condition, the vehicle alarm should not be triggered anymore when unlocking the door using a key.

5. Activate Panic Button Fix

This can be fixed easily. If presses the panic button by mistake, simply press it one more time, and this will deactivate it. If the key fob refuses to work, one may deactivate a vehicle’s alarm by simply putting the key in the vehicle’s ignition before starting the vehicle.

How to Turn off Car Alarm

Aside from the solutions discussed above, some other ways to turn off the unnecessary wailing of a vehicle’s alarm include:

Turning on The vehicle in┬ácertain instances, a noisy vehicle still gives a chance to drivers to turn on their ignition. Proceed if this opportunity exists because it could stop the vehicle’s alarm from causing a nuisance repeatedly in the entire neighborhood. If doing this fails to work, try to turn the key to the ACC position. Here, one can use vehicle features like a radio without necessarily turning on the engine. It could take some time and extra patience before it actually works.

Why do vehicle Alarms Stop Working When the vehicle is being Unlocked With a Key?

Locking or Unlocking The Vehicle Doors

Pressing the lock or unlock button on the remote key can, sometimes independently, stop the unnecessary alarm. Otherwise, a physical key should be tucked in the plastic controllers close to the door handle to lock or unlock vehicle doors.

Find the Shut-off Lever

Buying alarm systems that are not factory-fitted usually have a lever covered up close to the driver’s feet capable of shutting off or disabling the vehicle’s alarm. Go through the instruction manual of the alarm system to confirm if the vehicle’s alarm possesses this function. If a qualified technician installed the vehicle’s alarm, this information should not be new to the vehicle owner.

Take Out The Vehicle’s Alarm Fuse

If solutions like pressing the remote key or locking the vehicle doors fail to work, then removing the fuse controlling the alarm

from the vehicle’s fuse box will fix it. Just ensure the battery terminals are first detached to remove the fuse to avoid electrocution. Remember that this solution applies to older vehicles only because modern vehicles have integrated alarms fixed in their central electronic unit.

Remove The Wires

A person who has the mechanical knowledge to fix his vehicle’s alarm system can also do this without any professional assistance, although he may need an extra hand. Even if a lot of aftermarket alarm cables are found below the steering, this solution is not advisable for one who has a broad knowledge of the vehicle’s alarm system.

Reset The Vehicle’s Alarm System

Particularly for vehicles whose security setups come with independent alarm control modules, the alarm system can be reset if the alarm continues to go off late at night. Go through the manual to see how this can be done.

Totally Remove The Vehicle’s Alarm System

When all other options do not work, the last option is to shut down the whole system, which can be done easily in older vehicles. It can be done in two ways; partially by taking out the alarm unit or connections totally from the vehicle or by simply cutting the wires. Partial removal means one can choose to reconnect the vehicle’s alarm system later on. Meanwhile, a total removal involves disabling the whole system, which kills every chance to reconnect later. For more recent vehicles, disabling the vehicle alarm system requires software manipulation of some kind.

There are methods that can be used to shut off a vehicle’s alarm. There may even be the need for a tool that can be used to pull a fuse or a needle nose plier, as well as the owner’s manual, which comes in handy every time. What is essential is to fix the issue without delay to prevent being a nuisance to oneself as well as others.

What Can Make a Vehicle Alarm Go Off?

1. Hood Latch, Door, or Trunk Sensors

More recent vehicles have more sensors than their older counterparts, though a lot of alarm setups have hood latches, door, and trunk sensors to detect when any of these parts are opened.

These sensors work with a spring-triggered button near the circuit that allows power flow when the vehicle door is opened. This power triggers the dome indicator, which in return triggers the alarm if it is deemed necessary by the computer.

2. Shock Sensors

Shock sensors notice vehicle movement through metal contacts touching one another upon bumping into a vehicle that activates the circuit.

More complex systems can also detect the bump’s degree too, which makes the computer react appropriately. This also means should a person walking by bump into it, they are given a slight sound of the horn, but if the vehicle is hit with an object like a crowbar, there will be a very loud alarm.

It can be helpful for a vehicle to have systems that can detect differences between heavy and little bumps. Occasionally, a basic or sensitive alarm can be triggered by a pet jumping onto the bonnet, which will most likely disturb the whole neighborhood.

At times, very loud sounds can trigger a shock sensor due to the sound waves hitting the vehicle.

3. Tilt Sensors

A few thieves can play smart and quietly tow away the vehicle, which will ordinarily not trigger the vehicle alarm system. More complex alarm systems, however, have been built to manage this kind of scenario.

Tilt sensors notice when a vehicle changes position by utilizing mercury as a liquid conductive metal to seal up the circuit.

An alarm that has a tilt sensor is usually the only alarm type that can prevent a vehicle’s catalytic converter from being stolen, that is if the vehicle is actually jacked up by the thief.

4. Pressure Sensors

With equal air pressure within and outside a vehicle, breaking its window raises the pressure inside the vehicle for a short time. Pressure sensors notice the minor change in air pressure and send the computer a signal.

At times the pressure sensors can be a separate tool; however, in some vehicles, the speakers fixed in the vehicle by the manufacturers can actually aid in “listening” to the change in air pressure.

Speakers produce sound by moving around to cause a vibration in the air, which creates sound waves. Hence, these sound waves, in reverse, shake the speaker, and the sensors inform the computer of this movement.

5. Microphone Sensors

These listen detect sounds and are programmed to simply notice and send signals when they notice the glass is being broken only.

  1. Proximity Sensors

Sensors like this are basically used in extremely technical systems, like those of luxury vehicles. They can identify when a person stands within a very short distance of the vehicle and play warnings that were earlier recorded.

Frequently Asked Questions – Why do vehicle Alarms Stop Working When the vehicle is being Unlocked With a Key?

Will a car alarm stop after unlocking the doors?

A lot of vehicle alarms will go off after the vehicle doors are successfully unlocked using its keys or the proper key fob. When door locks fail to respond, it could be the case that the remote key batteries are dead.

How can one deactivate a vehicle’s anti-theft system?

Put the key in the ignition hole, then turn it once to activate the vehicle accessories without igniting the engine. Let the key remain in this position for a period of 10 to 15 minutes. Then, take a look at the anti-theft warning light again. If it has stopped blinking, return the key to its initial position and leave it for a couple of minutes.

Is there any need to reprogram a key fob after changing the battery?

Basically, reprogramming a key fob after a battery replacement is unnecessary. However, if it is not only the battery that was touched and some other internal connections and components were tampered with, it may become necessary to reprogram the remote key by reconnecting it with the vehicle again.

How can one unlock a vehicle without beeping?

Simply turn off the horn sound feature. To do this, press the lock as well as the unlock buttons on the key fob for a few seconds. Look out for the danger lights and wait for them till it flashes three times. Then, lock the vehicle doors and affirm the successful deactivation of the horn sound.

What can cause a car alarm to start sounding?

A lot of alarm systems can be easily triggered by vibration or shock sensors. They detect when the vehicle is being moved something, including an unsuspecting dog or even a thief.

Can low battery power trigger a vehicle alarm?

Generally, the battery transmits a signal whenever the engine is being started. With low battery power, the alarm will be triggered whenever the vehicle is turned on. Loon at it from the perspective of the vehicle, informing the driver it’s time for a battery replacement. A voltmeter can be used to check the battery’s power condition.

Why will a car alarm refuse to go off?

Some factors that could be responsible for this include low battery, faulty sensors, damaged key fob as well as connection problems. When the vehicle doors are not properly closed, it could also cause this problem. While an ECU or alarm reset will fix a lot of these issues, others may need professional expertise.

How can one know if a car’s anti-theft mode has been engaged?

A lot of recent vehicles have a warning light indicating that the vehicle’s anti-theft system is active. The sign for the anti-theft system on the dash has the picture, which has a lock and a vehicle. When it comes on and starts blinking, it is an indication that the vehicle’s anti-theft system has been triggered.

Will a car alarm drain the car’s battery?

Vehicle alarms fixed by vehicle producers usually do not cause trouble in any way; however, aftermarket alarms do not follow the same path. If properly installed, they use up a small quantity of battery power and will not drain the battery excessively. If Installed wrongly, then they can use up every bit of power in the battery.

Conclusion – Why do vehicle Alarms Stop Working When the vehicle is being Unlocked With a Key?

Vehicle alarms can be handy in keeping a vehicle safe from criminals and thieves, but the alarm going off when one is just attempting to open the vehicle with its key can put off the driver. There is no need to bother because this is not a permanent problem, as many factors could be the reason behind this. Fortunately, this problem is not difficult to fix.

This article examined some of the most popular factors that can trigger an alarm when simply unlocking the vehicle using a key. Hopefully, this write-up also served one of its purpose, which is to educate its reader on the steps to take and how to properly handle this situation the next time this problem springs up.

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