Why is airbag light is still on after ACM airbag control module was reset?

 
If the airbag light remains illuminated even after the crash data has been reset, it indicates that there's still an issue or fault in the Supplemental Restraint System (SRS).
 
Here are some reasons why the airbag light might still be on:
 

Faulty Sensors

One or more of the impact sensors might be damaged or malfunctioning.

Damaged Wiring or Connectors

Any damage to or disconnection in the wiring system of the SRS can cause the light to stay on. This can be from previous repairs, corrosion, or even rodents.

Clock Spring Issues

If the clock spring inside the steering column is damaged, it can affect the airbag's function and trigger the light.

Faulty Airbag Module

Even after resetting, the module itself could be faulty and might need replacement if it has internal hardware damage.

Seatbelt Pretensioner Issue

If the seatbelt pretensioner (which tightens the seatbelt in an accident) is faulty, it can trigger the airbag light. MyAirbags does rebuild seat belts.

Passenger Occupancy Sensor Issues

If the sensor in the passenger seat (which detects if someone is seated there) is faulty, the airbag system might detect a fault.

Other Faulty SRS Components

There are other components in the SRS system, such as the side airbags, knee airbags, or even seatbelt buckles, that, if faulty, can trigger the airbag light.

Battery or Charging System Issues

Low voltage or problems with the vehicle's battery or charging system can sometimes cause the airbag light to illuminate.

Aftermarket Components

Installing aftermarket components, like seats, radios, or alarms, might interfere with the vehicle's SRS system.

Software Issues

Sometimes, a software update or reflash is needed for the SRS system, especially in newer cars.

Incomplete Crash Data Reset

The crash data might not have been properly cleared. MyAirbags provides service to clear crash data.

Misdiagnosis

The original issue causing the airbag light might not have been addressed or was misdiagnosed.
 
To accurately diagnose the issue, you'll need to scan the SRS system with a suitable diagnostic tool to read the specific fault codes. These codes will give a more precise idea of where the problem lies. Given the critical nature of the airbag system, if you're not experienced with these repairs, it's recommended to consult with a professional mechanic or technician.