System Operation Check

When checking air bag system operation (also known as prove out system), and upon completion of each diagnostic test, check for faults in air bag system. To check system, turn ignition switch from OFF to RUN position. If AIR BAG warning light illuminates for approximately 6 seconds (3 seconds on Cougar) and then goes out, air bag system is functioning properly and no fault codes exist.
NOTE: On F250 Super Duty and F350 Super Duty regular and extra cab models, passenger air bag deactivation switch light must turn on and off in same manner as instrument cluster warning light during system operation check.
If a fault is detected in air bag system during initial system check, AIR BAG warning light will either fail to light, stay on continuously, or flash. Flashing may not begin for up to 30 seconds after initial bulb check (ignition turned from OFF to RUN). If AIR BAG warning light flashes, indicating a fault in system, diagnose and repair as necessary.
If a system fault exists and AIR BAG warning light fails to light, an audible tone will be heard, indicating AIR BAG warning light is out and service is required. The tone is a chime which sounds 5 sets of 5 beeps.