Broken Coil Spring: Symptoms, Causes & Repair
How do you recognize a defective clock spring?
A defective clock spring can be identified by an illuminated airbag warning light, a non-functioning horn, and failed steering wheel buttons. Often multiple symptoms occur simultaneously, as all electrical signals between the steering wheel and vehicle run through the same clock spring. The driver airbag may no longer be functional if defective.
The clock spring (also called a slip ring or spiral cable) sits between the steering wheel and steering column and transmits all electrical signals despite the steering wheel's rotational movement. If the internal conductor foil breaks, all functions running through it fail – affecting the airbag, horn, steering wheel buttons, and on newer vehicles, the steering wheel heater as well.
What symptoms does a defective clock spring have?
Typical symptoms include a continuously or intermittently illuminated airbag warning light, a failed horn, non-functioning multifunction buttons on the steering wheel, a defective steering wheel heater, and scratching or grinding noises when steering. Sporadic failures when turning the steering wheel are particularly typical.
| Symptom | Description | Safety Relevance |
|---|---|---|
| Airbag warning light illuminates | Continuously or intermittently when steering | Very high – driver airbag deactivated |
| Horn does not function | No signal when pressed | High – StVZO violation |
| Steering wheel buttons without function | Radio, telephone, cruise control do not respond | Low – comfort loss |
| Steering wheel heater failed | Heater no longer activates | None |
| Noises when steering | Grinding, cracking, or scraping | Medium – indication of defect |
| Sporadic failures | Functions fail only at certain steering angles | High – beginning cable break |
Typical failure progression
A clock spring defect often develops gradually: initially, failures occur only at certain steering angles – the warning light comes and goes. Over time, the cable break becomes larger and functions fail permanently. Noises when steering can be an early warning sign.
What are the causes of a defective clock spring?
The most common cause is natural wear of the conductor foil from years of steering movements. Each rotation of the steering wheel mechanically stresses the flat ribbon cable. Particularly frequent full lock steering, an incorrectly centered installed clock spring, or a foreign object in the housing accelerate the defect.
| Cause | Description | Frequency |
|---|---|---|
| Mechanical wear | Conductor foil breaks after years of stress | Very common |
| Frequent full lock steering | Maximum stress at the end stops | Common |
| Incorrect centering during installation | Clock spring not mounted in center position | Moderate |
| Foreign object in housing | Foil settles incorrectly and tears off | Moderate |
| Previous workshop visit | Not correctly centered after steering wheel removal | Moderate |
| Manufacturing defect | Known defect in certain model series | Rare |
What fault codes does a defective clock spring show?
In the fault memory of the airbag control unit, codes such as "Resistance too high" or "Interruption" in the driver airbag ignition circuit typically appear. Common codes are 00588 (Driver airbag ignition circuit resistance too high), B0070, or manufacturer-specific variants that indicate the interrupted connection to the steering wheel.
| Fault Code | Meaning | Indication of Clock Spring |
|---|---|---|
| 00588 | Driver airbag ignition circuit: resistance too high | Very likely |
| B0070 | Driver airbag ignition circuit interruption | Very likely |
| B0071 | Driver airbag resistance too high | Likely |
| 65535 | Internal error (sporadic) | Possible (with loose contact) |
How is the clock spring replaced?
The replacement requires removal of the driver airbag and steering wheel. The defective clock spring is replaced with a new part and installed precisely in the center position. Subsequently, the fault memory is cleared and the system is tested. The work may only be performed by qualified personnel.
- Disconnect battery: Minimum 10 minutes waiting time (capacitor discharge)
- Remove driver airbag: Loosen fastening screws/springs
- Remove steering wheel: Loosen center screw, mark position
- Remove clock spring: Disconnect connector, remove old clock spring
- Center new clock spring: Turn to stop, then exactly 3.5 turns back
- Install steering wheel: Place in straight-ahead position
- Install airbag: Connect connector, secure module
- Connect battery: System starts self-test
- Clear fault memory: Remove old codes
- Function test: Warning light must go out, test horn and buttons
Important: Correct centering is critical. If the clock spring is not installed in the center position, the conductor foil will tear at the next full steering lock – the defect will occur immediately again.
What does clock spring replacement cost?
The costs consist of the replacement part and workshop labor. A new clock spring costs between 25 and 325 euros depending on the vehicle model – simple versions are cheaper, variants with integrated steering angle sensor are significantly more expensive. For removal and installation, workshops typically charge 100 to 200 euros.
Does Airbag24 repair clock springs?
No, Airbag24 does not offer clock spring repair or clock spring sales. Our specialty is the repair of airbag control units as well as the sale of simulators for seat occupancy mats. However, if your airbag warning light is illuminated, the problem is not always the clock spring – often a defective airbag control unit is the cause.
- Airbag control unit repair: We repair defective airbag control units for all common brands and models
- Seat occupancy mat simulators: Suitable simulators for seat occupancy detection in our shop
- Consultation: Are you unsure whether the control unit or clock spring is defective? We help you with diagnosis
Frequently asked questions about defective clock springs
Here you will find answers to the most important questions about the defective clock spring.
Can I continue driving with a defective clock spring?
The vehicle is drivable, but the driver airbag does not function and the horn has failed. Both are safety-relevant and TÜV-relevant defects. In an accident, the driver has no airbag protection. The defect should be remedied promptly.
Is the clock spring a wear part?
Yes. The conductor foil is mechanically stressed with every steering movement and wears out over the years. In vehicles with high mileage or frequent city driving (lots of steering), the defect occurs more frequently. It is a normal aging process.
Can I replace the clock spring myself?
This is strongly discouraged. Removing the driver airbag poses significant hazards – if handled improperly, the airbag can deploy unintentionally and cause serious injury. Work on the airbag system may only be performed by trained qualified personnel.
Why do the horn and airbag fail at the same time?
Both functions run through the same clock spring. If the conductor foil breaks, all signal paths are interrupted – airbag ignition line, horn, steering wheel buttons, and heater. This is why multiple functions often fail simultaneously.