F 450 4WD Super Duty V10-6.8L VIN S (1999)
Standby Power Supply: Description and Operation
The Electronic Crash Sensor (ECS) module includes an internal backup power supply. This feature provides sufficient backup power to deploy the air
bags in the event the battery or battery cables are damaged in a collision before the safing and air bag sensors close. The backup power supply will
deplete its stored energy approximately 1 minute after the battery ground cable is disconnected.
The ECS also employs a "keep-alive" period that allows the module to remain powered and active for approximately six minutes after switching the
ignition key from the RUN position to the OFF position. During this period, the module is performing backup power supply regulation and crash
discrimination while being completely capable of all deployment functions.