Headlights blink when the engine is running, what to do

If the headlights blink while the engine is running, you need to find out the cause of the problem and fix it. It does not occur just like that and most often signals a malfunction in electrical equipment or other malfunctions. If you do not pay attention to the blinking of the light, this can lead to various troubles - from the failure of the lamps at the most inopportune moment to the breakdown of the generator, which will make it impossible to continue moving.

Causes of blinking headlights when the engine is running

The power supply system for the headlights is standard on all machines. The current is supplied through the wire, and the minus is connected to the car body. When the engine is running, the generator is responsible for power supply. In this case, the problem is almost always observed when the engine is idling, when the voltage in the on-board network is minimal.

Voltage above normal

A working generator should produce a voltage of 14 to 15 volts, this is the normal range that provides power to all equipment in the car.If the indicator is higher, this leads to overloads and disruption of the systems, which is why the lights begin to blink. But this is not the most dangerous, because expensive electronics can fail due to overloads, which will entail much higher repair costs.

Such a malfunction most often leads to the replacement of the generator. Or it needs to be given for diagnostics in order to identify problems and fix them. It is undesirable to drive in this case, so as not to overload the electrical equipment.

The voltage must not exceed 15V.

Voltage below normal

This option is much more common, since the generator and other elements wear out during operation. Over time, this leads to a decrease in voltage, most often the problem is as follows:

1. Deterioration of the diode bridge or other elements of the generator. In this case, the equipment is either repaired or replaced. Often, the operation of this unit is disrupted by worn bearings that prevent the shaft from rotating normally.
2. The alternator drive belt is loose. In order for the motor to transmit force to generate current, the belt must be well tensioned. If it is weakened, current generation deteriorates.
3. Strong wear of the battery leads to the fact that it can no longer hold voltage. And the generator is not able to provide all current consumers at idle, which is why the headlights flicker.
4. High load on the generator. This can be when using powerful audio systems and other elements that consume a lot of energy. In this case, simply turn down the sound or turn off something that overloads the network.

Sometimes the problem arises due to the fact that when replacing the generator, an option with a lower power was supplied and it simply is not enough for normal operation.

Other reasons

Headlights may also flash due to malfunctions in other systems. The most common options are:

1. Damage or poor contact of the ground wire coming from the headlight to the car body.
2. Problems with the power supply in LED lamps. This is especially common in cheap products. After a short time, the elements begin to work intermittently and the problem can only be solved by replacing them.
3. Deterioration of xenon lamps. This light source has a certain service life and when the replacement period approaches, the bulbs may flash. Also, when using xenon, this may indicate malfunctions or interruptions in the operation of the ignition unit.

If one lamp began to shine yellow, then its resource is coming to an end.

Video: We are looking for the reason when the headlights and all the lights in the cabin flicker.

Troubleshooting Rules

To quickly identify the cause of the flickering light, you must follow a simple instruction. To work, you will need a multimeter or voltmeter, without it you will not be able to check the indicators. The process consists of the following steps:

1. The voltage that the generator produces is checked. If it does not correspond to the norm, you need to remove the assembly and take it for diagnostics or call in a car service so that all the necessary work is done there.
2. On the muffled engine it is necessary to check the tension of the belt going to the generator. When pressed hard with your thumb, it should bend slightly. If the tension is weak, you need to tighten the belt.
3. The battery voltage is measured. When the charge is low, the battery should be recharged.If the battery does not take a charge, you need to check the electrolyte level and measure its density (in serviced models). Unattended ones just change.
4. Not only the output voltage on the generator is measured, but also the current flowing directly to the headlight connector. If the difference is large, then if there are problems with the wiring or contacts, they should be fixed.
5. The ground wire from the headlight to the body is checked. It is necessary to ring it, as well as clean the contact point and clamp it well using a washer.
   Ground wire contact often deteriorates due to corrosion.
6. When blinking only one lamp, the easiest way to check it is simply by changing the light sources in places. If flickering on the same light source, then the problem is in it. This is true for xenon and LED equipment.

If the lamp malfunction indicator lights up on the instrument panel, it means that the lamp is not working properly.

What mistakes are made when repairing headlights

If the repair is done incorrectly, the problem may return. Therefore, it is worth remembering simple tips that will help you avoid mistakes:

1. Only pairs of lamps should be changed. Even if the problem is with one, you can’t even set the same one, since the resource of the light sources is different and, as a result, the system will be disrupted.
2. Clean contacts in case of voltage loss. This measure is temporary and the problem will return soon. It is much better to put an additional relay coming from the battery, through which the headlights are powered. Then there will be no voltage drop.
3. Don't buy cheap lamps, especially for LEDs and xenon. Their resource is much less than stated.

Video block: Flickering light at idle.

Getting rid of the blinking light is not difficult, since finding the problem does not take much time and does not require sophisticated equipment. Most often, you can fix the problem on your own, the main thing is to correctly find out the cause of the flicker.