Common Causes:
* Faulty Crash Sensor: These sensors detect impacts and trigger the airbags. A malfunctioning sensor can trigger the light.
* Low Voltage: A weak battery or faulty charging system can cause the light to illuminate.
* Loose Connections: Worn or loose connectors in the wiring harness, particularly under the seats or near the steering wheel, are common culprits. Vibration can loosen these over time.
* Faulty Airbag Control Module (ACM): This is the "brain" of the system. A malfunctioning ACM is a serious issue and often requires replacement.
* Faulty Airbag(s): A problem with the airbag itself (though less common than other issues) can cause the light to remain on.
* Faulty Seatbelt Pretensioner: These devices tighten seatbelts in a collision. A malfunction can trigger the light.
* Clock Spring: This is a spiral cable in the steering column that allows the airbag and other components to rotate with the steering wheel. A break in the clock spring is a frequent cause.
Less Common Causes:
* Faulty Occupant Sensor: Some vehicles have sensors that detect the presence and weight of occupants.
* Wiring Harness Damage: Damage to the wiring harness, perhaps from rodents or corrosion, can cause intermittent or constant light illumination.
What to Do:
1. Don't ignore it: A malfunctioning airbag system can be life-threatening in a crash.
2. Have it diagnosed: You *must* have the vehicle's airbag system professionally diagnosed. A simple visual inspection is unlikely to pinpoint the problem. An OBD-II scanner may show a diagnostic trouble code (DTC), but often specialized SRS scan tools are needed for a complete diagnosis.
3. Find a reputable mechanic: Ensure the mechanic has experience working on older vehicles and is familiar with diagnosing SRS systems. Improper repair could create further safety hazards.
4. Repair promptly: Once the problem is identified, get it repaired immediately.
Important Note: Working on the airbag system yourself is extremely dangerous and strongly discouraged. Airbags contain powerful explosives and improper handling can result in serious injury or death. Always leave this type of repair to a qualified professional.
