Car burglar alarm common fault analysis and solution
Jan 17, 2019

The use of the   car anti-theft alarm system is realized by the car power supply and some circuits of the car itself . Once the anti-theft device fails, it will affect the normal use of the vehicle. This article analyzes the causes of some common faults and introduces the processing methods. Most of the faults are handled by the user.

  Example 1. Fault phenomenon: The remote control operation does not work. When the remote control function buttons are pressed, the red LED of the remote control does not light.

  Analysis of the cause: This fault is mostly in the remote control itself. There are several situations: (1) the battery is exhausted; (2) the battery positive and negative reeds are rusted or poorly contacted; (3) the remote control is rained or entered. Water, oil immersion, etc. In this regard, the board can be taken out, washed with industrial alcohol, dried with a household hair dryer or left to dry naturally before use.

  Example 2. Fault phenomenon: The remote control distance is getting shorter and shorter. When the signal is transmitted, the brightness of the LED of the remote controller becomes dark or flickering.

  Analysis of the cause: This phenomenon is mostly caused by insufficient battery power and battery replacement. In addition, it is not recommended to adjust or replace the components of the remote control yourself to avoid further losses.

  Example 3. Fault phenomenon: A certain function key of the remote control fails. When the key is pressed, the LED indicator does not light.

  Analysis of the cause: A function key is invalid (other function keys are normal). The function key is damaged or the key pin is disconnected from the solder joint of the circuit board. Most of the buttons on the remote control are micro-switches. When using them, use light force and pay attention to waterproof, anti-drop and heavy pressure.

  Example 4. Symptom: When the remote control is not used, the LED indicator often lights on itself, or it is always on as long as the battery LED is installed, and the operation of the remote control does not respond.

  Analysis of the cause: When the remote control does not press the button, the indicator light often lights itself. Generally, the button of the remote control is mechanically damaged. The performance of the button is not good, no flexibility, you can change the button. For the code skip type remote control, pressing the remote control function keys does not respond. After replacing the battery or reinstalling the battery, the LED indicator lights for 20 to 40 seconds, and then no response. This means that the button has short-circuit damage. If the hand feels no abnormality, use the multimeter R×1 file to test each button on the road, and then replace the short-circuit button.

  Example 5. Fault phenomenon: The vehicle automatically turns off after 30 to 40 seconds and enters the alarm state. After the anti-theft function is released, the above situation is repeated during driving, and so on.

  Analysis of the cause: This phenomenon is caused by operating the remote controller in the car, causing secondary automatic anti-theft. As long as the door is opened and closed after pressing the anti-theft function button, the problem can be solved. The remote control of the car anti-theft system is limited by the volume, and the function buttons are generally no more than four, so that each button is often given several functions. In a certain state, the functions controlled by the same function button are different, or a function is more The keystrokes are completed and should be used with special care. Example 6. Fault phenomenon: The vehicle is in anti-theft state, and the anti-theft failure is cancelled by the remote controller.

  Analysis of the cause: In the anti-theft state system, due to the remote control or system host failure (the host is mostly remote control receiving circuit failure), causing the anti-theft failure (the remote control loses control of the system), the car direction light (double lamp) flashes The alarm horn sounds constantly and the vehicle cannot start driving. At this time, the anti-theft system can only be temporarily removed, which requires the user to pay attention to the general installation position of the anti-theft system host. If you do not understand the position of the anti-theft device, you can find the system host according to the LED indicator of the anti-theft system, the ultrasonic sensor probe or the alarm horn, etc., and unplug the connector of the anti-theft system host and the vehicle. In addition, some remote car anti-theft alarm system hosts have an emergency release function, and the use of the anti-theft device can be suspended without having to remove the system host.

  Example 7. Fault phenomenon: The car anti-theft system works normally, the ignition motor is running normally, but the vehicle cannot be started.

  Analysis of the cause: This phenomenon may be caused by an alarm or an electrical failure of the car itself. The judgment method is: short-circuit the two thick wires of the ignition device (12V/30A, generally placed near the car key door) of the car alarm device attachment. If the vehicle can be started at this time, the anti-theft system is faulty, and most of them are relays. damage. If the vehicle is still unable to start after short-circuiting the two thick wires of the ignition relay, the circuit of the car itself is faulty. In addition, when the vehicle encounters a bumpy road during driving, it is easy to turn off the flame or instantaneously extinguish the fire. Special attention should be paid to whether the normally closed contact of the ignition relay is cut off or the wiring is loose.

  Example 8. Symptom: When turning on the car while turning the light, the other side is also lit.

  Analysis of the cause: This fault is the diode breakdown of the voltage output of the car direction light (double lamp) controlled by the anti-theft system (in some models, the two diodes are inside the main unit, some are attached to the connection line), and the replacement of the same type of diode can be eliminated. malfunction.

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