Certain models contain a Supplemental Restraint System better known as an airbag that is meant to prevent a driver and front seat passenger from suffering severe injury in a head-on or frontal crash. This system consists of air bag mounted on center of the steering wheel and right-hand side of the instrument panel while the sensing /diagnostic part is devise mounted on the mid of automobile. The airbag inflater module consists of a housing that has the cushion, inflater units situated at the central part of the steering wheel with the inflater assembly on the rear of the housing. If an electrical signal is sent from the system, the gas is expelled through a hole and the bag fills almost immediately. A coil assembly on the steering column transmits this signal regardless of the position of the steering wheel, When an electrical signal reaches the igniter that is in the air bag, this igniter transforms the electric signal into heat and get the sodium azide/copper oxide powder to produce nitrogen gas for inflation. The SAS sign-carrying airbag placed on the instrument panel trimming above the glove compartment is larger than one installed on the steering wheel-it includes the inflater with the igniter, the bag, the reaction housing, and the trim cover. The trim cover of the air bag looks like the instrument panel it also has a molded seam that opens up when the air bag inflates. The sensing and diagnostic module supplies current to the air bag system in a collision even if the battery is disconnected and checks the system each time the vehicle is started and if it's working, the "AIR BAG" light will illuminate. If a fault is found this light will light up, blink, or produce a beeping sound which will warrant service. Measures to take include; Verify that the car alarm's activation code for the anti- theft car stereo before disconnecting the battery, disarm the car alarm system by pointing the wheels straight ahead, define the ignition to Lock position, disconnect the car battery negative terminal and waiting for not less than 90 seconds while the back-up power supply is drained. It is recommended to use gloves when handling an airbag module and to always point the airbag opening away from the operator's body, and to avoid placing the airbag module with the opening down. Any component in an SAS cannot be measured for its resistance as plugging in an ohmmeter could trigger the airbag. Also, electrical welding equipment should not be connected in any vehicle with air bags without the disconnection of the Yellow Airbag connector and the live Air bag modules must be taken to the dealer for proper disposal through a controlled Dependent Air bag deployment.