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Air bag light

The air bag light is another warning indicator that may illuminate on your dashboard. Airbag problems can be much more complicated to repair than let's say check engine light problems.

In fact it is recommended that servicing of this important safety system should be performed by professional technicians.

Since the supplemental restraint system (SRS) has been deployed since the 80s the problem of the illuminated air bag light is becoming more common on these aging systems.

It is for this reason that I decided to write a quick article about what I find most often causing the light to flash or stay on.

Keep in mind that these are very complicated systems and many things can cause the warning light to flash, stay on or not come on at all. In a perfect world everybody would have a scan tool capable of communicating with the SRS module. Some vehicle manufacturers require a scan tool for diagnosis.

Other manufacturers automatically flash the code from the dashboard warning light. You'll have to get an auto repair manual for your specific vehicle to determine how to read the flash codes because procedures will vary greatly between manufacturers.

About the airbag indicator light

This dashboard mounted indicator is designed to let the driver know that the system is ready to do its job. Of course this would be to deploy the quick inflating bag during a hard collision. On most vehicles the lamp is operated by the main control module.

The light should illuminate when the key is turned from the off to the on or run position for a bulb check. On some models the light will flash briefly while the system runs a complete diagnostic.

But when the engine is running the light should go out. If a malfunction is uncovered during the quick automatic diagnostic test the airbag light may stay on continuously or even flash.

This could mean a problem that would prevent the airbag from deploying in the case of an accident. For this reason diagnosis should be performed as quickly as possible.

Common cause for airbag lights

One of the components that get a constant workout in any SRS system is a part that most mechanics will call the clockspring. The airbag clock spring allows for constant electrical contact to the steering wheel mounted module and related components at all times.

The clock spring is located between the steering wheel and the steering column and contains a conductive flat ribbon that maintains this needed contact during steering wheel rotation.

This important component feeds power from the vehicle's battery up to the module and is ultimately responsible for providing the needed energy to deploy the bag.

If electrical contact should be disrupted between the module and the airbag clock spring a code will be set and the air bag light may flash to indicate that there is a problem.

Since this is one of the only components that are constantly moving in the SRS system it is also one of the most common failures.

Replacement of the SRS clockspring requires the removal of the airbag assembly and the steering wheel as well. Some special tools may be required to complete the repairs.

Accidental deployment when removing the air bag is not common but is possible. For these reasons it is best to have the clock spring replaced by a qualified auto repair shop.

Air bag special tools and parts

Diagnosis of many air bag system faults is impossible without some special tools. On Ford vehicles from the late eighties well into the nineties a special tool called a simulator (pictured to the right) is used to aid in diagnostics.

Because the circuit remains open when you unplug the module many testing procedures cannot be performed. The simulator provides the correct resistance and specifications as a good part would. This allows the diagnosis to safely continue.

The Ford special simulator tools are essential for body repair shops but can also be helpful for mechanics trying to diagnose air bag lights. Some diagnostic tree charts in the ford service manual require the use of one of these air bag simulators because they will simulate a complete circuit for diagnostic purposes.

Give this SRS resource page a bookmark or

More articles about dashboard warning lights and common problems that cause them are grouped on my auto scan tool page. This next link will take you there from this page about the air bag light

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