Back-Up Power Supply
WARNING: This page is about a different car, the 2002 Lincoln LS. However, it is still accessible from the selected car via links, so may be relevant.
A back-up power supply is located inside Restraints Control Module (RCM). If battery or battery cables are damaged in a collision before sensors close circuit, back-up power supply will provide electrical power to deploy air bags. Back-up power supply will hold a deployment charge for about one minute after negative battery cable is disconnected.