If you own a certain model of 4Runner, it is possible to add a combo device with both an airbag (SRS) and a seat belt for driver and passenger safety in front crashes. The system features packages - the first in the steering wheel, a second in the panel above passengers, and a third sensor at the center to monitor activities. The airbag inflator unit inside the steering wheel inflates the bag when the system gets an electrical signal. A special coil wire sends steering-wheel-independent signals below the steering wheel module, triggering the sodium azide/copper oxide reaction, which makes nitrogen gas to inflate the bags. The passenger side airbag covers the glove compartment space and holds four different parts: inflator, bag, housing, and trim. The control unit for the airbag system powers and checks the system when starting the car, and shows the "AIR BAG" warning light when everything works correctly. If an issue affects the airbag, we'll get both a warning light and an audible alarm telling to fix it right away. Before touching steering wheel or SRS components, you must disarm the system by setting the wheels straight, turning the ignition to LOCK, removing the negative car battery, and waiting at least two minutes until the backup power shrinks. Keep the airbag module opening facing away from the body, and avoid putting it on anything with the opening downwards. We can't test the electrical resistance of SRS parts, and we need to cut airbag power connections before using electrical welders. When people have crashed with us, they need to drive their car back to a dealer to make sure the airbags work correctly and get thrown out properly.