Seat switch JAGUAR X308 1998 2.G Repair Manual

Supplemental Restraint System - Air Bag Supplemental Restraint System
(SRS)
Description and Operation
Supplementary Restraint Air Bag System

Airbag/SRS units provided for driver and fro nt seat passemger protection, are installed in the center of the steering wheel,
the passenger side fascia and the oute r wing of each front seat. A single point sensing unit (SPS) mounted on the
transmission tunnel, below the ra dio, provides fully electronic impact sensing, control and diagnostics for the front airbags
Deployment of each side airbag is initia ted by a side impact sensing module (SISM) installed in the adjacent 'B' post. Each
SISM senses and electronically processes a crash pulse and if this exceeds the 'must fire' threshold, transmits a fire signal
to the SPS unit. The SPS unit monitors wh ole vehicle motion and on confirmation of a crash condition, transmits a firing
current pulse to the appropriate airbags. In the event of a side only impact, the SPS will send a current pulse to the airbag
on the struck only. Neither th e non-struck side airbag nor the frontal restraint system will be deployed under these
conditions. The airbag system can only be activated wh en the ignition switch is in position II or III.
Side Air Bags