Do-it-yourself car alarm siren repair

During the operation of the car, it becomes necessary to repair its systems and assemblies. The security system is no exception in this regard. To save money, you can do it yourself. In this article, you will learn how to repair car alarms and key fob with your own hands.

It is conditionally possible to divide all alarm malfunctions into the following types:

• nutritional problems;
• wiring problems;
• software failure;
• false positives;
• key fob malfunction.

Let's take a closer look at each of the malfunctions in the car alarm.

Often the causes of incorrect alarm operation are power problems. This can happen both with the equipment installed on the car and with the car alarm key fob. The power failure of the system occurs due to a discharged vehicle battery. The machine stops responding to the owner's commands. The battery that serves as a power source for the key fob can also be discharged. In this case, the lamp and the display of the device will turn off. A decrease in battery charge can be noticed in a timely manner by reducing the range of the key fob.

The reason for the de-energization of the system is sometimes wiring defects. Over time, the contacts oxidize, which leads to the termination of the transmission of electricity. The wires themselves may also be damaged. This happens during the installation of additional equipment or when trying to steal the car. Another reason is faulty fuses. The same symptoms appear as with power problems - the car does not respond to commands. This is provided that the key fob is in working order.

Sometimes car alarm malfunctions are caused by incorrect operation of the control unit - the "brain" of the system. This is the result of a software failure.

These malfunctions are caused by errors in setting up or installing a car alarm. If the sensitivity of the sensors is set too high, the alarm will be triggered at the slightest shock or vibration. The triggers can be caused by small dry tree branches falling on the machine, rain or even a loud sound. Sensors set to optimal sensitivity, but mounted on plastic parts, will also not work correctly. The fact is that plastic amplifies the vibrations that the sensors perceive. When heated, this material expands, which can cause sensors to trip.

During operation, the key fob may start to work incorrectly or even break. The reasons for this are wear and various damage caused by a fall or exposure to water. A cracked display significantly reduces the information content and ease of use of the security system. Dropping the key fob can also cause damage to the quartz.

Before starting car alarm repair, it is necessary to find the cause of the malfunction. Completely different breakdowns can have the same symptoms. To accurately determine the cause of the malfunction, it is necessary to consider all possible options in stages.

You need to start with a keychain. Inspect it for mechanical damage and traces of water. If the key fob has been immersed in water, condensation will form on the inside of the display cover. The operation of such a device (if it turns on) will be unstable. If the key fob did not fall and fell into the water, but the display is off and nothing happens when you press the buttons, then the battery is to blame.

If the key fob is fully functional, but nothing happens when you press its buttons, then there can be two reasons for this - strong external interference or problems with the car and the alarm. Try to bring the key fob to the part of the car where the car alarm antenna is installed and press the button. If nothing happens, then faults must be sought in the machine itself or in the alarm equipment installed on it.

Next, power and wiring diagnostics are performed. Check the battery charge and inspect its terminals for oxidation. The completeness of the battery charge can be easily determined by the operation of the on-board electronics. If everything is normal, then the next step is to check the wiring. To do this, you need a special tester, which calls the contacts. Inspect the wires for mechanical damage. Special attention should be paid to fuses. Usually they are in a box, which is located on the wire coming from the positive terminal of the battery.

If the cause has not yet been found, then the defect in the control unit or the failure of its software is to blame. It will not be possible to eliminate such a defect with your own hands, but with a software failure everything is much simpler - it is enough to carry out simple manipulations, which we will discuss below.

Most often, repairs require a car alarm key fob. The buttons wear out and begin to respond poorly to pressing, and the device itself may fall on the asphalt or in a puddle. Button repair includes disassembling the case, cleaning the contacts and replacing the button pads (if necessary). To raise the recessed buttons, you can make a plastic substrate that is glued to their seats on the board.

Most often, when a key fob falls, quartz comes off its board. To eliminate this defect, it is enough to disassemble the key fob and solder the quartz to its original place.

To fix cracks in the display, you need to completely replace it. Remove the old display, clean the contacts and solder the cables of the new display. The process itself is not very complex and requires initial soldering skills. The difficulty lies in finding a new display. You can hardly find it in stores, so you have to order from China via the Internet. Defects caused by water ingress cannot be repaired by yourself.

Power and wiring problems are solved by cleaning battery contacts and terminals, as well as replacing fuses and damaged wires. In order not to do unnecessary work, use the tester to find the exact cause of the malfunction, and then eliminate it.

To eliminate the problem of false alarms, it is necessary to adjust the sensitivity of the sensors. The adjustment process is extremely simple. To do this, screw in or unscrew the adjusting screw located on the sensor housing.

To resolve software failures, you must reboot the system. To do this, de-energize it by disconnecting one of the terminals from the battery for a few minutes. If this does not help, then reset the car alarm to factory settings. A step-by-step reset instruction can be found in the instructions for your alarm model.

The best way to test a car alarm is to use it for its intended purpose. Arm the car and try to open the doors, trunk or hit the car. You should hit the wheels, hood and windows, gradually increasing the force of impact. After checking the sensitivity setting of the sensors, open the car doors with the key and try to start it, also using the key. The alarm should go off. Check the rest of the functionality, depending on the specific model, the functionality will be very different, we suggested how to check the basic and general alarm functions.

Most of the problems associated with the operation of car alarms can be fixed by hand.It is better to entrust the repair of the control unit and other complex electronics to specialists. If, after following the above recommendations, the breakdown is not eliminated, then you need to contact the car service. To continue driving with a broken alarm, you need to master the process of turning it off with a secret button, which you can read about in the instructions for the car alarm.

In conferences, there are often questions about the types of sirens, their interchangeability and connection. This article provides some thoughts on simple sirens, in the hope that it will be useful to someone when installing or replacing a siren.

Very important: when connecting the ground of the siren, it is advisable to always use a welded standard bolt or nut on the body.

simple sirens.

Simple or non-autonomous sirens are often called bells, they can be single-tone, multi-tone, vary in power and body shape. But what they have in common is only two wires for connection. Most often, the black wire is connected to ground, and the red wire to the alarm. It is better to check the exact connection according to the alarm installation diagram. There are alarms that control the siren by a minus (ground) signal, for example, Clifford Cyber ​​5. In such cases, the positive wire of the siren is connected to the positive terminal of the battery using a fuse.

The big disadvantage of these sirens is that when the wires are cut off, the siren stops, as in the case if the battery terminal is thrown off or it is discharged.

But there are advantages - these sirens can be compact and maintenance-free, which means they can be hidden in hard-to-reach places. It is convenient to install such sirens as additional ones, replace standard autonomous sirens with them or install them discreetly in the car interior.

Of course, there is an exception, Clifford sirens such as Medalion or the like, which are a speaker. But they are disabled in a similar way.

If your siren has many tones, then the number of tones can be reduced to one or you can choose the ones you like. On some models, there is a window on the siren's case covered with a rubber band, under it there are six jumpers - removing the jumpers disables the corresponding tone of the siren, later models have jumpers on the board in the form of wires or printed conductors, cutting which leads to similar results.

Typically, the consumption of such sirens does not exceed 2A.

Any simple sirens are interchangeable. They can also replace autonomous sirens with the appropriate connection depending on the control signal.

The occurring defects of these sirens are manifested in the form of a quiet sound or its complete absence.

The siren's performance is checked by applying a signal (+) from the standard battery terminal to the red wire of the siren, in this case the second wire of the siren must be securely connected to the vehicle ground. If the siren is controlled by a ground signal, then applying this signal to the black wire of the siren, while the second wire must be securely connected to the (+) battery terminal using a fuse.

Note that the siren ground wire is always black, and the signal control wire (+) can be of a different color, for example, white as in Scher-Khan alarms.

If the siren worked when a signal was given, then the malfunction is either a break in the control wire from the alarm, or a failure of the control transistor. The integrity of the wire is checked by applying a control signal to the wire directly coming from the alarm connector. The serviceability of the transistor is checked by a probe consisting of an LED and a resistor. With a positive control signal, a resistor with a nominal value of 1 kOhm is connected in series to the alarm output to the siren, the anode of the LED (in the form of a triangle shown in the diagrams) is connected to the resistor, the cathode of the LED is connected to ground (shown as a dash in the diagrams).With negative control, the cathode of the LED is connected to the alarm output, the anode to the resistor, and the other end of the resistor to the positive terminal of the battery. If the output transistor is good and the panic signal is turned on, the LED should light up.

If the siren did not work when the control signal was applied directly, then the cause of the malfunction lies in the siren itself. This may be a break in the speaker coil, a failure of the transistors of the siren output stage or the tone shaping circuit. With a quiet siren signal, the output stage may partially burn out, or water may enter the siren's reflective deflector. The last reason is eliminated by drilling a small hole in the siren deflector.

Very important: when connecting the ground of the siren, it is advisable to always use a welded standard bolt or nut on the body.

Standard standalone sirens.

We call them standard to distinguish them from the sirens of Clifford, Cobra, Sikura, etc. The difference between autonomous sirens and those described in the previous article is that they have a service key and a built-in battery, as well as four wires for control and power.

Disabling the autonomous siren with the key does not disable the alarm and its interlocks, with the exception of specific sirens and monoblock alarms. The last two types are distinguished by the presence of more than four control and power wires.

There are always red and black wires, they are respectively connected to the plus of the battery and to the mass of the car. It is clear with the mass, this was said at the very beginning. The plus is connected to the power wire of the alarm and as close as possible to the connector. Let me explain why. The first - the siren will be protected by a fuse, the second - if the alarm harness going under the hood is cut, then the autonomous siren will immediately turn on the signal due to a power loss (provided that it was turned on with the key).

There are two more wires left, which raise questions - where to connect them. Please note that when checking the siren, namely when the plus and ground are connected, it does not scream, regardless of whether the key is turned on or not. Here, in order for the siren to scream, these two wires serve. Usually they are signed "positive trigger" - a positive trigger and "negative trigger" - a negative trigger. One of these wires is connected respectively to the alarm control wire. If in the “Panic” mode a signal (+) appears on the wire, then a positive trigger is used, and if the ground signal is (-), then a negative trigger, respectively. With this connection of the siren, the main consumption goes through the power wire from the battery, and only low-current control from the alarm system. And in this case, you can connect an additional simple siren if desired.

Some kind of autonomous sirens, of course with a reservation, can be cited as the fact that there are sirens, even with the key turned off, they can scream when a control signal is given. Others must be turned on with a key.

The advantage of these sirens, as mentioned above, is that after cutting the wires, the siren continues to scream due to its own battery. Of course, she screams a little quieter, but this does not make the hijacker feel better. And with a good internal battery, it can scream for quite a long time, although five minutes will be enough at night to fulfill its function. It is advisable to occasionally check the condition of the internal battery of the siren by disconnecting the standard battery terminal or removing the alarm fuse when the siren is turned on with the key, so that this advantage does not turn into a disadvantage.

About the shortcomings. Since there is a key and a lock, it means that there must be access to the siren, and at the same time it cannot be hidden far away. The internal batteries of the siren may be destroyed, and the siren will turn into a simple one from an autonomous one, or worse, it will start to consume increased current, thereby discharging the standard battery.

You can check the health of the siren and the alarm output stage using the method described at the end of the article on simple sirens. The only difference is that the power on the red wire must be present, and the control signal is applied to the corresponding input to check the siren's performance. It remains to add only that the siren lock may malfunction, which sometimes crumbles or collapses, which makes it impossible to either turn the siren on or off.

Siren connection diagrams:

To check the performance of sirens, the conductor with point “A” is the place where the control signal is given. The verification method is described in the article about ordinary sirens. A prerequisite is the presence of power and ground on the siren wires.

A) Connection of a siren with positive control from the alarm. The dotted line shows the possible connection of an additional simple siren.

When replacing an autonomous siren with a simple one, according to the scheme at point “A”, control from the autonomous siren is disconnected, and the simple siren becomes the main one. Insulate the power wire of the autonomous siren.

B) Connection of a siren with ground signal control. The dotted line shows the possible connection of an additional simple siren.

When replacing an autonomous siren with a simple one, according to the scheme at point “A”, control from the autonomous siren is disconnected, and the simple siren becomes the main one. Insulate the power wire of the autonomous siren.

C) Connection of an independent siren with protection against disconnection of the alarm connector. The diagram shows two options.

The first is using a standard connector. If there is an unused wire in the connector - for example, a positive door trigger or an output to an additional channel, then by cutting off the printed conductor, you can solder a jumper inside the board. This contact will become the power supply wire of the autonomous siren, and in case of power failure the siren will turn on due to the built-in battery.

The second option is if you solder a wire inside the alarm to the power contact and bring it into the alarm harness, then you get the same result when the wire breaks or the connector is disconnected.

Similarly, it is possible to protect a siren with mass control.

D) Connection of several sirens.

Using this scheme, you can connect several additional simple sirens, hiding them, for example, in the cabin, trunk or in hard-to-reach places under the hood. Fuse 15 Amp - is the main one for powering additional sirens, the relay decouples the alarm output by current. Three-ampere fuses for each of the additional. sirens are needed if a hijacker finds a siren and closes the wires, the smaller fuse rating of this siren will burn out, and the rest will remain working. In an emergency, the general fuse can be switched off.

Because the power supply of the autonomous siren is taken from the general power supply of the alarm, then in this case it can also be protected according to the scheme (B).

Good day to all.

To make it clearer about what we are talking about, we are talking about a siren with an alarm system, but instead of the standard “wow-wow” music plays whatever you want and upload.
I will not post diagrams and assembly information. This information on Drive is full enough to score in the search for “musical siren”.
Well, if you think like that, then at the time of the generation it’s no longer a “thumb” but an “index finger”, and when it’s customary to choose what the soul likes - why not! After all, we also select the ringtone on the phone or the beep melody, and if possible, then change the siren melody.
Personally, I was guided by the article - the author - ZiperRZN
As it is now known, the "reader" of music from the SD card is the controller - Attiny85.
For some it's easy, for some it's difficult, and for some it's fantastic. But I am more than sure that not always after the assembly this miracle did not sing for someone, this article is dedicated to just the mistakes due to which it may not sing.

one.Firmware - you should pay special attention to Fuse-bits, or rather how to set them in the firmware using the manual for the firmware. It's very simple - the manuals indicate 1 or 0, in the firmware - 1 is a checkmark, 0 is no checkmark. further on the picture I drew arrows so that it was more clear to which bit which parameter.

Such a fuse bit as - RSTDISBL special attention to it, since it refers to the “RESET” MK leg, if there is no checkmark on it, then it will be programmed for output and it will no longer be possible to reset and reflash the MK, the exit is to treat with the help of - “Fuse bit the doctors". The Attiny 85 WAV read firmware has a "Stereo" firmware, this foot is used to output the second channel. You don't need an alarm! Use “Mono” firmware!

2. SD card. I didn’t sing precisely because of the SD card, I tried it on old 64MB and 128MB SD cards, it didn’t sing! until I changed to 4GB.
It must be formatted with the FAT32 file system.

3. The file itself. The format is known as WAV. I flashed my firmware - "FULLSIRENA",
It reads a Wav file with parameters:
Codec — “Microsoft Wave” “PCM”
Bit - 8
Mono
Frequency - up to 48 000Hz
Example on the program - Sony Sound Forge

The power supply, or rather the stabilizer, is MANDATORY - 3.3 volts, because. more simply disable the SD card!
Firmwares that “FULLSIRENA” and that “sd8p_mo” are absolutely working!
I tried everything in expanded form on experimental boards.

Car alarms, like any other car system, can sometimes fail. If you are not an expert in the field of electronics, then it is better to entrust the repair of an alarm on a car in terms of its brains to a professional auto electrician.

There are situations when the alarm malfunction is not related to the operating system, and in this case it is quite possible to fix the breakdown yourself. In order not to panic ahead of time, not to transport your car to a car service, you need to have an idea about the typical car alarm malfunctions.

In this case, self-repair of the alarm system on the car will save you from unnecessary worries and unforeseen blows to the budget. To repair an alarm on a car, traditional driver tools should always be at hand: screwdrivers, wire cutters, electrical tape, a couple of wires, a tester (a light bulb with two wires for “ringing”).

Important! If your car alarm is still under warranty, then, of course, you should not interfere with it yourself.

• Nutrition. The alarm does not respond to your pressing, or performs actions that you did not order. We start the check with the key fob, namely with the battery. Disassemble and key fob and replace the battery - it does not take much time. A characteristic sign of a low battery is the LED becomes dimmer, or the range of the key fob remote action decreases. Another reason for the key fob to not work may be the ingress of water on it (when used in the rain).
• Wiring. No matter how complex or advanced the car alarm is, whether it is the usual “beep” of the AOS (auto security alarm) or the GSM alarm, under the influence of external factors, the contacts at the junctions always oxidize. That is, the repair of a car alarm always begins with the ringing of contacts.
• The LED lights up brightly, but the alarm does not respond to pressing. In this case, the repair of the alarm on the car begins with finding out the reasons for this phenomenon. The "brain" of the AOC could freeze, because in any case we are dealing with a mini-computer. Reboot required. It is necessary to remove the terminal from the battery (any), i.e. de-energize the system and after a couple of minutes put it back on. If the alarm is working, you can fix the terminal, no - try rebooting 2-3 more times. If it doesn’t work out, then we proceed to the next step in repairing the alarm on the car - checking the fuses.
• Circuit breakers. If a separate wire with a separate hanging fuse box comes from the positive terminal of the battery (or from wires with a constant “plus”), check the fuse. Since we started, at the same time you need to check the serviceability and performance of the main energy consumers of the car (standard fuses): emergency gang, sound signal.During this test, the negative power is called (this type of testing can be carried out if you know where the AOC central unit is located). In this case, the AOC is rebooted by the following method: remove the connector from the unit and reconnect it. If the beep sounds, no big deal.

If your efforts to repair the car alarm are unsuccessful, you will have to contact a car service, the cause of the malfunction turns out to be deeper.