Ford Mercury Villager 1997 Owner's Manual page 152

The Air Bag Supplemental Restraint System consists of:
driver and passenger air bag modules (which include the
inflators and air bags),
one or more impact and safing sensors,
a system diagnostic module,
a readiness light,
and the electrical wiring which connects the components.
The diagnostic module monitors its own circuits, the air bag
electrical system, the air bag readiness light, the air bag power and
the air bag inflators.
Inflated driver side air bag
148