General Description
The Supplemental Air Bag Restraint System is designed to provide increased accident protection for front seat occupants IN ADDITION TO that provided by the three point safety belt system. Safety belt use is necessary to obtain the best occupant protection and to receive the full advantages of the supplemental air bag. FORD RECOMMENDS THE USE OF SAFETY BELT SYSTEMS FOR ALL VEHICLE OCCUPANTS.System Component Locations:
The Supplemental Air Bag Restraint System consists of two basic subsystems:
1. Driver air bag (and optional passenger air bag)
2. Electrical system, including impact sensors and electronic diagnostic monitor
DRIVER AIR BAG
The driver air bag is mounted in the center of the steering wheel. The module consists of the following components:
^ Inflator
^ Bag Assembly
^ Mounting plate and retainer ring
^ Steering wheel trim cover
CAUTION: The driver air bag is serviced as a complete assembly.
Inflator
The inflator assembly is not a serviceable item. When the sensors close, signaling a crash, battery power flows to the air bag inflator. Inside the inflator, an igniter converts the electrical signal to thermal (heat) energy, causing the ignition of the inflator gas generant. This ignition reaction combusts the sodium azide/copper oxide gas generant in the inflator, producing nitrogen gas, which inflates the air bag.
Driver Air Bag
The air bag is constructed of neoprene coated nylon, is 711 mm (28 inches) in diameter and fills to a volume of about 0.065 cubic meters (2.3 cubic feet) in approximately 40 milliseconds. It is not a serviceable item.
Mounting Plate and Retainer Ring
The mounting plate and retainer ring attach and seal the bag assembly to the inflator. The mounting plate is also used to attach the trim cover and to mount the entire module to the wheel. These items are components of the air bag module and cannot be serviced.
Steering Wheel Trim Cover
When the air bag is activated, tear seams moulded into the steering wheel trim cover separate to allow inflation of the bag. The cover is a component of the air bag module and is not serviceable.
PASSENGER AIR BAG, OPTIONAL
Passenger Air Bag Module:
The passenger air bag is mounted in the RH position of the instrument panel above the glove compartment. The air bag consists of the following components:
^ Inflator
^ Bag Assembly
^ Reaction housing with mounting hardware
^ Trim cover
NOTE: Vehicles that have the letters SRS located above the glove compartment come equipped with a passenger air bag. For vehicles without a passenger air bag, refer to instrument panel cover description.
CAUTION: The passenger air bag is serviced as a complete assembly.
Inflator
The passenger air bag inflator is not a serviceable item. As with the driver air bag, an igniter inside the inflator converts to battery power to thermal (heat) energy, causing ignition of the gas generant. The ignition reaction causes combustion of the sodium azide/iron oxide gas generant producing nitrogen to fill the bag. Since the passenger air bag is much larger than the driver air bag, it contains more gas generant in a different inflator configuration to produce more nitrogen gas.
Trim Cover
The thermo-plastic trim cover is textured and painted to match the surface of the instrument panel. It is constructed with a moulded-in tear seam that separates when the air bag inflates, and hinges out of the way during deployment. Its main function is to retain the air bag in the reaction housing during vehicle operation. It is not a serviceable item.
Passenger Air Bag Delete Bracket
Vehicles which are not equipped with the optional passenger air bag will have the passenger air bag delete bracket. Circuit 286(Y) from diagnostic monitor Pin 7 is the optional passenger air bag signal and is grounded for driver only air bag systems. Circuit 286 (Y) goes to a one way connector near the passenger air bag harness connector. For driver only air bag systems, this connector is secured to the passenger air bag delete bracket which is located behind the finish panel above the glove compartment.
DIAGNOSTIC MONITOR
The air bag diagnostic monitor continually monitors all air bag system components and wiring connections for possible faults in the system. If the diagnostic monitor detects a fault in the air bag system when the ignition switch is in the ON position, a diagnostic trouble code will be displayed on the air bag warning indicator. Performing system diagnostics is the main purpose of the diagnostic monitor. THE DIAGNOSTIC MONITOR DOES NOT DEPLOY THE AIR BAGS IN THE EVENT OF A CRASH! The crash sensors are "hard wired" to the air bags, and therefore, the crash sensors determine when to deploy the air bags.
Several important features of the air bag diagnostic monitor and its functions within the system are described in Features and Functions. It is necessary that you understand these key features and functions. They will enable you to better understand and perform more efficient air bag system diagnostics.
Features and Functions
^ The diagnostic monitor illuminates the air bag indicator for approximately 6 seconds when the ignition switch is turned to the ON position and then turns it off. This indicates that the air bag indicator is operational. If the air bag indicator does not illuminate or if the indicator stays on or flashes at any time, a fault has been detected by the diagnostic monitor.
^ Diagnostic trouble codes may not be displayed for approximately 16 seconds after the ignition switch has been switched to the ON position. This is the amount of time it takes the monitor to perform all tests and verify system faults, if present.
^ Diagnostic trouble codes are displayed as a series of flashes and pauses of the air bag indicator. Each diagnostic trouble code, or series of flashes represent a two digit number. For example, a Diagnostic Trouble Code 32 is displayed as follows:
Flash flash flash - (one second pause) - flash flash - (three second pause)...
flash flash flash - (one second pause) - flash flash - (three second pause)...
^ If a system fault exists and the Air Bag Indicator is malfunctioning, an audible tone will be heard indicating the need for service. The tone is a series of five sets of five beeps. This DOES NOT indicate a diagnostic trouble code 55. It means that the indicator is out and a system fault exists that requires service.
^ If a fault exists that makes unwanted air bag deployment possible, the air bag diagnostic monitor has an internal thermal fuse that will blow automatically. This removes all power to the air bag deployment circuit. The air bag indicator will flash the appropriate code to indicate the suspect circuit. The thermal fuse is controlled by the diagnostic monitor and is not serviceable.
NOTE: The thermal fuse does not blow because of excessive current flowing through it. DO NOT attempt to jumper out the thermal fuse with a circuit breaker of any other type of fuse.
^ Diagnostic trouble codes are prioritized numerically so that if two or more different faults occur at the same time, the fault having the highest priority will be displayed first. The highest priority fault will be displayed until it is corrected. After if has been corrected, the next highest priority fault will be displayed.
^ The air bag diagnostic monitor includes an internal back up power supply. This feature provides sufficient back up power to deploy the air bags in the event that the battery or battery cables are damaged in a collision before the crash sensors close. The back up power supply will deplete its stored energy approximately one minute after the positive battery cable is disconnected.
WARNING:
^ The back up power supply energy must be depleted before any air bag component service is performed. To deplete back up power supply energy, disconnect the positive battery cable and wait one minute.
^ The air bag simulator(s) must be removed and the air bag(s) reconnected before the system is reactivated.
STEERING COLUMN WHEEL AND CLOCKSPRING
The steering column has a clockspring assembly to transfer electrical signals from the steering column to the steering wheel for the air bag system.