There are 3 crash sensors mounted in the front of the vehicle. There is another sensor mounted in the passenger compartment of the vehicle which monitors the deceleration rate of the vehicle upon collision. When any of the crash sensors and the deceleration sensor are simultaneously activated, the air bag will be deployed. The air bag system does contain a warning lamp which will illuminate and stay lit if there is a problem within the system. The complete air bag system is controlled by the diagnostic module unit. The module unit contains a diagnostic feature which will display a coded warning lamp display when trouble does exist.