(Updated on April 20, 2020)
An airbag or supplemental restraint system (SRS) is a safety device made for vehicles. It is meant to keep the driver and front passenger restrained in the event of an accident.
For instance, if a driver crashes their vehicle into the back of another vehicle at a fast speed, the airbag module inside of the steering wheel will inflate almost instantly. That way, it prevents the driver from banging their head or upper body against the steering wheel, dashboard, or windshield.
The airbag will deflate within seconds after inflating so that the driver is not suffocated by the airbag. The airbag system will activate whenever a large decrease in acceleration is detected or when your vehicle collides with another hard object.
There are several parts which make up the airbag system. Each one of these parts has a specific function in making the airbag inflation occur at just the right time.
Below are the seven main parts of an airbag system and an explanation of what each one does.
1) Airbag Inflator
The airbag inflator is part of the airbag module, which also includes the airbag as well. The job of the airbag inflator should be self-explanatory. It is to quickly inflate the airbag in the airbag module so that it comes out and shields you from flying out of the car.
The inflation system is able to create this inflation effect by mixing potassium nitrate and sodium azide to create nitrogen gas. Once this gas enters the airbag, the inflation effect will happen instantaneously.
2) Crash Sensors
The airbag system depends on crash sensors so that the airbag module will know when to inflate the airbag. These crash sensors will detect when the car has a sudden halt in its acceleration.
Anytime the car crashes into a solid object while traveling at 15 miles per hour or higher, the crash sensors will activate the airbag inflation system.
3) Diagnostic Monitoring Unit
Every time that you start your vehicle, the diagnostic monitoring unit will run a test on the airbag system to make sure it is functioning properly. If you have already been in an accident and had your airbag inflate, you will need to take your vehicle to a dealership or auto repair shop that deals with airbags so that the airbag system can be reset.
Otherwise, the diagnostic monitoring unit will keep warning you about your airbag system being malfunctioning.
4) Indicator Lamp
The indicator lamp is basically the warning light for the airbag system. When your vehicle conducts a diagnostic check on the system, the indicator lamp will illuminate for a few seconds.
But if there is a problem with the airbag system, the indicator lamp will stay lit.
5) Connection Coil
The connection coil is what connects the steering wheel with the airbag system. This would apply to the driver’s side airbag in a vehicle.
Some vehicles also have airbags for the front passenger side of the cabin as well. In that case, the connection coil would exist in the dashboard area above the glove compartment.
Of course, the airbag itself is another part of the airbag system. This is the bag which inflates in front (and/or side) of the driver or front passenger upon collision with another vehicle or solid object.
The airbags are typically made from a nylon fabric. It is coated with a heat shield so that the fabric stays protected in case there is any scorching.
See Also: Airbag Replacement Cost
7) Wiring Harness
The wiring harness represents the series of wires which connect all the components of the airbag system together. If there is just one wire that is damaged or nonfunctional in any way, then it will throw the entire airbag system out of order.