FORD 2004 Expedition v.2 - Manual (Page 163)

Front safety belt usage sensors
The front safety belt usage sensors detect whether or not the driver and
front outboard passenger safety belts are fastened. This information
allows your Personal Safety System to tailor the air bag deployment and
safety belt pretensioner activation depending upon safety belt usage.
Refer to Safety Belt section in this chapter.
Front safety belt pretensioners
The front outboard safety belt pretensioners are designed to tighten the
safety belts of the driver and front ouboard passenger firmly against the
occupant’s body during a collision. This maximizes the effectiveness of
the safety belts and helps properly position the occupant relative to the
air bag to improve protection. The safety belt pretensioners can be either
activated alone or, if the collision is of sufficient severity, together with
the air bags.
Front safety belt energy management retractors
The front outboard safety belt energy management retractors allow
webbing to be pulled out of the retractor in a gradual and controlled
manner in response to the occupant’s forward momentum. This helps
reduce the risk of force-related injuries to the occupant’s chest by
limiting the load on the occupant. Refer to Safety Belt section in this
chapter.
Determining if the Personal Safety System is operational
The Personal Safety System uses a warning light in the instrument
cluster or a back-up tone to indicate the condition of the system. Refer
to the Warning Light section in the Instrument Cluster chapter.
Routine maintenance of the Personal Safety System is not required.
The Restraints Control Module (RCM) monitors its own internal circuits
and the circuits for the air bag supplemental restraints, crash sensor(s),
safety belt pretensioners, front safety belt buckle sensors, and the driver
seat position sensor. In addition, the RCM also monitors the restraints
warning light in the instrument cluster. A difficulty with the system is
indicated by one or more of the following:
• The warning light will either flash or stay lit.
• The warning light will not illuminate immediately after the ignition is
turned on.
• A series of five beeps will be heard. The tone pattern will repeat
periodically until the problem and warning light are repaired.
2004 Expedition (exd)
Owners Guide (post-2002-fmt)
USA English (fus)
Seating and Safety Restraints
163