Rear Air Bag Sensor
WARNING: This page is about a different car, the 2002 Lexus ES 300. However, it is still accessible from the selected car via links, so may be relevant.
The rear air bag sensor is mounted in lower D-pillar, behind outboard bolster of rear seat back. It consists of an air bag sensor, safing sensor and diagnosis circuit. It receives signals from the rear air bag sensor and determines whether side curtain air bag module must be deployed or not.