Why does the needle of the speedometer twitch?

Often, the electrical circuits drivers almost do not pay due attention. Wires from the moment of purchase of the car almost never change. As a rule, this is not necessary, as long as everything works. But sooner or later there comes a time when the wiring starts to pour. The arrow of the speedometer is twitching, the dashboard lighting is floundering, etc. All this is resolvable, so let's deal with this issue in more detail.

What do I need to know?

Often the problem with the speedometer is related to electronic malfunctions. Although much depends on the car. For example, if the arrow of the VAZ-2107 speedometer twitches, then it's not necessarily the case in the wiring. The speedometer in this car is a mechanical type, there is at least a minimum of wires. Therefore, very often the problem is a cable that has lost tension.

At the same time, it may be in a faulty speed sensor. Many motorists check its efficiency first. It's much easier than dismantling the dashboard, repairing the malfunction and reassembling it. Let's look at the same in more detail with the main malfunctions of the speedometers on some brands of cars and consider methods for their elimination.

Problem with the speed sensor

In order to understand the question of why the arrow of the speedometer is twitching, it is necessary to become more familiar with the design of the car. For example, the domestic classics did not have a speed sensor. The system worked like this. At the checkpoint was located a motor (drive), which, during the car's movement, twisted a cable going to the speedometer.

If the motor was out of order, then the arrow at the instrument panel "died" and always showed "0". But most modern cars are equipped with a speed sensor, which is installed in the gearbox. It determines the speed mode with practically no error and transmits the data to the speedometer by means of wires. From the same wire and the sensor, the data also come about the distance traveled, that is, to the odometer.

Typical malfunctions

Talk about the reliability or unreliability of this sensor is not necessary. On some cars, it works during the entire lifetime, but on others it often breaks down. Nevertheless, there are a number of typical problems that motorists face:

• Failure due to old age. Every electronic device, regardless of quality, has its own resource. Therefore, it can fail at any time.
• Mechanical effect. Simply put, damage to the sensor housing or wiring. If any work has been done to remove and install the sensor, it is likely that it has been damaged.
• Oxidized, parched or broken wires. Also, the trunk works out its own, if it has not changed for a long time.
• The sensor does not fit the given model of the car. In this case, do not rely on the correct readings of the speedometer.

Troubleshooting methods

Usually, the operability of the control devices can be restored by replacing the speed sensor. As an example, consider the car "Hyundai Accent". The arrow of the speedometer twitches - we go to buy a new speed sensor in the store. With a large mileage of this brand of cars, this is quite a typical problem for him, which many motorists face. If the box is mechanical, the problem is most often solved by replacing the cable. Lubrication with VD-40 also helps, but this is more of a temporary solution, so in the future the problem can return.

As for the automatic transmission, sensors are installed there, which often fail. Change them will not be difficult. Let's see how to do it and what we need to do the work.

Replacing the speed sensor

If the arrow of the speedometer VAZ-2107 twitches, then it is necessary to replace the cable or worn out gears, the faces of which have already worn out during the operation of the car. This rule is practical for all cars that are equipped with manual transmission. The speed sensor is installed in the automatic box. Let's look at the example of "Accent" consider the replacement process.

For the work we will need to buy original speed sensors worth 800-900 rubles apiece. From the instrument you need a key for 10 and 12, as well as the corresponding heads. There are two sensors in total. The first is located on top of the box, the second is on the bottom. To get to the top, you need to dismantle the air filter box and remove the battery with the platform. After that, use the key for 10 to unscrew the old one and install a new one. The lower sensor is behind the left wheel. To get to it, you need to remove the protection box and the front part of the fender cover.

Wrong wiring

As already noted above, the wires are oxidized with time, bend and just crumble. In the end, this leads to the loss of contact completely, which previously appeared, then disappeared, which led to an incorrect operation of the speedometer.

This problem can be solved in several ways. The simplest is to solder the wires and put them on a heat shrink. The problem may arise elsewhere, but this may not happen. The second method is to replace the entire braid. A more laborious and complex method, but as a result - the normal operation of the wiring for a long time. Also it is necessary to understand that if the wire is bare, it can be shortened by mass. In this, too, there is nothing good, so if you noticed this, then it's worth trying to fix the problem as soon as possible.

The arrow of the speedometer VAZ-2109 is twitching

Often, removal of the instrument panel will be necessary to correct the problem. It takes a long time, although almost everyone will cope with this task. To perform the dismantling, you need to get the radio and cigarette lighter, emergency lamp and unscrew all the necessary fasteners. Now you can proceed with immediate repair.

If the arrow of the speedometer twitches at speed dialing, then, most likely, it's in the drive, which went out of order. Therefore, you need to remove the drive, gears, and seals. The latter must be replaced with new ones. Next it is desirable to carry out the defect of the gears. If the faces are lapped on them, then we change them.

In addition, it is advisable to check the cable. It is likely that it touches something during the ride, which is what causes the jumps of the arrow of the speedometer. If necessary, replace and lubricate the cable. Then we perform the assembly.

Atypical breakdowns

If the arrow of the speedometer twitches (2109 is a VAZ or another model - it's not important, a breakdown of this type is inherent in many cars), and the above method did not help, that is, several more options. One of them is the jamming of the arrow in a certain position. Therefore, when speed dialing, the instruments can display normally, but at some point there will be a jump. Solve the problem by disassembling the instrument panel and repairing the speedometer. It is likely that you will need to remove the arrow and lubricate it or change it to a new one.

Another atypical failure is the failure of the gears after twisting the run on the mechanical speedometer. It is rather rare and says that the masters correcting the run did not stand on ceremony with the car. But on the electronic speedometer when twisting the run, the system can be locked, and the "Chek Engin" error appears on the dashboard. Lastly, it's worth looking at the onboard computer, but this only applies to electronic systems.

How to replace the cable

Over time, the cable decays and gradually begins to fail. The first time the problem manifests itself in the form of the jerks of the speedometer and tachometer. If you do nothing, then the devices soon and completely cease to show the speed of the car and mileage. To solve the problem, it is necessary to drive the car to a pit. On the side of the engine compartment is the drive cable. After disconnecting the protective cover, unscrew it with the usual carabiner wrench. Now we can disconnect the wire.

It is desirable to first disassemble the instrument panel. The reason is that after we detached the cable from the drive, it must be disconnected from the speedometer. We unscrew the nut and take out the wire through the engine compartment. In this case it is desirable to remember how it passed, so that later there were no problems with its installation. Two types of instrument panels were installed on the VAZ-2109: low and high. Accordingly, the length of the cables is different, so when buying with you it is desirable to have a sample, so as not to be mistaken.

A few important nuances

Here we are, in fact, figured out why the arrow of the speedometer can jerk. As you can see, there can be a lot of reasons. But, faced with such a problem, does not necessarily immediately go to the SRT. Faults can often be eliminated on their own, of course, if there is time and desire.

Ironically, with electronic systems in this case, everything is much simpler. In most cases, all ends with a banal replacement of the speed sensor or wiring. Another thing is that this sensor for some cars is worth a lot of money. In this case, you can try to find a decent analogue with the help of Internet directories. But openly Chinese products, which beckon its low cost, it is better to bypass. After all, such a sensor can please the owner of the car with correct work for a short time, or even not work right after installation.

Finally

The problem of mechanical speedometers is most often the critical wear of the main mechanisms. For example, under the influence of high humidity and salts, the cable rotates. If at some point the speedometer stops showing, then the case is clearly in the cable. In fact, the twitching arrow is not uncommon. Many motorists prefer not to pay attention to this problem at all and leave it at that. It is much worse when the revolutions start to float at idle.

As for some modern cars of famous brands, for example, "Mercedes" or "Audi", then it is sometimes difficult to do anything on their own. In this case, it is still better to visit dealers or service stations. But repair an old "Volkswagen" or VAZ will not be difficult even for a beginner. The main thing is to thoroughly approach the solution of the problem and have at least a minimum of the necessary instrument. In the most neglected cases, it makes sense to change the speedometer drive, but this only applies to mechanical options. This is similar to replacing the speed sensor, but somewhat more complicated and expensive. Here, in fact, and all that you need to know about the problem and the methods of its elimination.