The modern car is a complex electronic organism where each node is connected to a central control unit. One of the key elements that ensure the link between the driver and safety and comfort systems is the steering-line. It is this component that allows you to control multimedia, cruise control and airbags without interrupting the electric circuit when the steering wheel is rotating.
Many owners Hyundai Solaris, Kia Rio more expensive Toyota Camry face a situation when the signal stops working or the SRS error lamp lights up on the panel. In 80% of cases, this is the culprit. Understanding how it works and why it fails will help avoid costly repairs to the service and diagnose the problem yourself.
In this article, we will analyze the design of the device in detail, consider the typical symptoms of malfunctions and walk through the replacement steps. The steering train is the only mobile electrical contact in the steering column, transmitting a signal from the steering buttons to the onboard network. Ignoring its condition can lead to failure of the airbag system at a critical moment.
The design and principle of operation of the spiral contact
The under-wheel plume, often referred to as a spiral contact or airbag tape, is a flexible printed circuit board rolled into a spiral. It is placed in a plastic case, which is attached directly to the shaft of the steering column. The main engineering task of this unit is to ensure uninterrupted transmission of the electrical signal when the steering wheel is repeatedly rotated in both directions.
Inside the case is a thin copper tape with applied conductive tracks. When turning the steering wheel, the tape is unwinded on one side and wound on the other, like a roulette or measuring tape. The design is designed to have a margin of length exceeding the maximum steering angle. This prevents the chain from breaking even in sharp maneuvers or parking with wheels turned upside down.
The number of contacts on the train depends on the configuration of the car. In the basic versions, it can be only two wires for signal and mass, while in rich trim levels their number reaches ten or more. They are responsible for:
- 🚗 Transmitting the activation signal of the driver's airbag.
- 🎵 Control of audio system and media messages from the steering wheel.
- ⚙️ The operation of the cruise control buttons and speed limits.
- 📞 Managing hands-free communication and phone calls.
It is important to understand that spiral-contact It's a disposable element. Its internal structure is not rebuilt after the physical rupture of the tracks. Attempts to solder or glue the tape, as a rule, lead to unstable operation and can cause a failure of the security system.
When installing a new plume, always make sure that the steering wheel is strictly in the center, and the plume itself is exposed to a neutral position (usually marked with marks), otherwise it will break at the first turn of the steering wheel.
Typical symptoms of a plume malfunction
Diagnosis of malfunction of the steering plume often does not require complex equipment, since the symptoms are manifested clearly and affect the usual functions of driving. The first and most alarming bell is a lighted indicator. SRS or Airbag on the dashboard. This means that the control unit does not see the airbag chain, which is most often caused by a cliff in the plume.
However, the problems may not only concern security. Owners often notice that the buttons on the steering wheel stop responding. For example, you hit Volume Up, but the music doesn’t get louder, or the tracks switching is chaotic. Sometimes there is a “floating” fault effect: in the morning the buttons work, and after the trip stop, or vice versa.
Another bright sign is a broken sound signal (claxon). Since the signal button is located on the airbag, the current to it goes through the same plume. If the sound of the beep is lost and the media buttons do not work, the probability of a failure of the plume is close to 95%. There may also be a cruise control failure that simply stops activating.
It is worth noting that in winter the symptoms may increase. Low temperatures make the plastic of the case more fragile, and oxidized contacts less conductive. If you notice that after a frosty night the car begins to "glutch" in terms of steering wheel electronics, it is worth conducting an audit of the unit.
Why it fails: the main reasons
The resource of the steering plume directly depends on the manner of driving and the operating conditions of the car. The main reason for the failure is mechanical wear conductive tracks. Over time, copper thins, microcracks appear, which eventually lead to a complete break in the chain. The average resource of quality original parts is 150-200 thousand kilometers, Chinese analogues may not live to 50 thousand.
The second common cause is improper installation or dismantling of the steering wheel. If the steering wheel is removed, the plume was not fixed in the central position with a special stopper (or plastic plug), at the first turn of the steering wheel, the tape is stretched to the limit and breaks. This is a classic mistake of beginners trying to save money on the service.
External factors also influence:
- 💧 Moisture entering the steering column (for example, when washing the engine or leaking seals).
- 🔥 Overheating of the cabin in the sun, leading to deformation of the plastic plume body.
- ⚡ Voltage surges in the onboard network, breaking through the insulation of thin tracks.
- 🛠️ Mechanical damage in unqualified repair of the steering rack or column.
⚠️ Attention: Never try to rotate the steering wheel with the plume or airbag removed without first fixing the mechanism. This will definitely lead to a break in the new part.
Diagnosis: multimeter or scanner?
Before buying a new part, you need to make sure that the problem lies in the plume, and not in the pillow, buttons or control unit. The easiest way to diagnose the first is to visually examine and check for symptoms. If everything tied to the steering wheel (signal, buttons, pillow) does not work, then the culprit is almost found.
A more accurate check will be required multimeter. You need to take off the steering wheel and get to the connectors of the plume. Calling contacts, you need to rotate the steering column (or simulate rotation, carefully rotating the inside of the plume) and monitor the readings of the device. If resistance tends to infinity or jumps, contact is broken.
However, the most reliable method is a computer. diagnostics OBDII scanner. By connecting to the car, you can count the error codes from the SRS block. Errors like Open Circuit Driver Squib or Resistance Too High are a direct indication of a cushion chain break. The scanner will also show if other modules (such as an audio unit) see the buttons on the steering wheel.
| Symptoms. | Probable cause | Method of verification |
|---|---|---|
| Airbag lamp on fire | Crushing the pillow chain | Error scanner/Counterbrain |
| Signal's not working. | Break of button contact | Multimeter vertebra |
| Volume's up. | Oxidation of contacts | Visual inspection / Replacement |
| The cruise's not working. | Failure of a particular track | Scanner diagnostics |
Can I drive with a faulty plume?
Technically, the car will go, the engine will work, but you will be left without the driver's airbag. In addition, in some models (for example, Kia / Hyundai) if an SRS error can block the operation of some comfort systems or horn, which is prohibited by traffic rules.
Instructions for replacing the steering plume
Replacement of the plume is a procedure of medium complexity, requiring accuracy and a minimum set of tools. Before the start of work, it is mandatory remove the plug from the battery And wait 10-15 minutes. This is critical to discharging the capacitor in the airbag module and preventing the accidental firing of the pyropatron.
The process begins with the removal of the steering wheel. Depending on the brand of the car, this may require screwdrivers (Torx) or special keys. On modern cars, you often need to remove plastic plugs on the sides of the steering wheel to access the bolts of the cushion mount. After unscrewing the bolts, the pillow is carefully removed, and its chips are disconnected.
Then the central nut of the shaft is unscrewed, and the steering wheel is removed. Under it you will see the plume itself, fixed to several screws. When the sleeves are removed, the old part is removed. Installation of the new is done in reverse order, but with the observance of important nuances.
☑️ Checklist before assembly
When installing a new plume, make sure it is in the "zero" position. Usually there are marks on the case (triangles or arrows) that should match. If the plume is new, it often comes with a transport yellow locker. Don't take the lock out. until the steering wheel is fully installed! Only when the steering wheel is put on and screwed, the retainer is carefully removed, releasing the spiral.
⚠️ Attention: It is strictly forbidden to apply voltage to the connectors of the airbags when checking "for a spark". This can lead to detonation of the pyropatron and serious injuries.
Original or analogue: which to choose?
The auto parts market offers a variety of options, from expensive original boxes to cheap counterparts from China. Since the steering tail is responsible for safety, saving on it is risky. Original details (e.g., Mobis for Korean cars or Toyota Genuine Parts) undergo strict quality control and guarantee the declared resource.
High-quality analogues from well-known brands of autoelectrics (such as: Hans Pries/Topran, Febi, ERA) are also a good choice. They are often cheaper than the original, but are produced in the same factories. The main thing is to avoid “nouneim” packaging without marking, where the plastic can crack at the first installation, and the tracks are made of an alloy with high resistance.
When choosing, pay attention to the number of contacts. Even if you have a basic configuration without a cruise, it is better to buy a plume with a full set of contacts (for the "rich" version). In the future, this will allow you to install control buttons without replacing the entire node. The price of a full set is usually not much higher than the cut.
Choose a plume with the maximum number of contacts for your steering wheel model – this will ensure compatibility when upgrading the equipment and often means thicker, more reliable tracks.
Frequently Asked Questions (FAQ)
How much does it cost to replace a plume in the service?
The cost of work varies from 1000 to 3000 rubles depending on the region and the complexity of removing the steering wheel (some cars need to disassemble half of the torpedo). The cost of the part itself (from 1500 to 8000 rubles).
Can the sleeve be repaired with rations?
Theoretically, you can seller the wiring to the rupture, but this is a temporary solution. Mechanical stress during the rotation of the steering wheel will quickly destroy soldering. In addition, interference with the SRS system can lead to incorrect operation of the pillow. It's safer to replace the whole knot.
Why does the Airbag error burn after replacement?
Perhaps you forgot to remove the transport lock from the new plume, the connectors are poorly snapped, or an error in the control unit remained in memory and requires a scanner reset. Also check if the minus was removed from the battery before work.
Will the car be suitable for another model?
Only if it is a single platform (e.g., Kia Rio and Hyundai Solaris often have interchangeable parts). It is important to match the number of contacts, the shape of the body and the location of the fastening holes. Check the OEM numbers.