Seat Belt Switch: Operation

WARNING: This page is about a different car, the 2005 Jeep Grand Cherokee. However, it is still accessible from the selected car via links, so may be relevant.

The seat belt switch is designed to provide a status signal to the seat belt switch sense input of the Occupant Restraint Controller (ORC) indicating whether the driver side front seat belt is fastened. The ORC uses the seat belt switch input to determine the status of the driver side front seat belt. The ORC then sends electronic messages to the ElectroMechanical Instrument Cluster (EMIC) to control the seat belt indicator based upon the status of the seat belt switch input.

A spring-loaded slide with a small window-like opening is integral to the buckle latch mechanism. When a seat belt tip-half is inserted and latched into the seat belt buckle, the slide is pushed downward and the window of the slide exposes the Hall Effect Integrated Circuit (IC) chip within the buckle. The field of the permanent magnet induces a current within the chip. The chip provides this induced current as an output to the ORC. When the seat belt is unbuckled, the spring-loaded slide moves upward and shields the IC from the field of the permanent magnet, causing the output current from the seat belt switch to be reduced.

The seat belt switch receives a supply current from the ORC, and the ORC senses the status of the driver side front seat belt through its pigtail wire connection to the seat wire harness. The ORC also monitors the condition of the seat belt switch circuit and will illuminate the airbag indicator in the EMIC then store a Diagnostic Trouble Code (DTC) for any fault that is detected in the seat belt switch circuit. For proper diagnosis of the seat belt switch, a diagnostic scan tool is required. Refer to the appropriate diagnostic information.